Refer to the following exhibits:
Exhibit #1:

Exhibit #2:

Refer to the following Study the exhibits carefully. The switchport output in Exhibit #1 displays the default settings of interface FastEthernet 0/13 on switch TestKing1. Figure 2 displays the desired interface settings. Which command sequence would configure interface FastEthernet 0/13 as displayed in Exhibit #2?

A.
TestKing1(config-if)# switchport trunk encapsulation dot1q
TestKing1(config-if)# switchport mode dynamic auto
TestKing1(config-if)# switchport trunk native DATA
TestKing1(config-if)# switchport trunk allowed vlan add 1,10,20

B.
TestKing1(config-if)# switchport trunk encapsulation dot1q
TestKing1(config-if)# switchport mode dynamic desirable
TestKing1(config-if)# switchport trunk native vlan DATA
TestKing1(config-if)# switchport trunk allowed vlan 1,10,20

C.
TestKing1(config-if)# switchport trunk encapsulation dot1q
TestKing1(config-if)# switchport mode trunk
TestKing1(config-if)# switchport trunk native DATA
TestKing1(config-if)# switchport trunk allowed vlan 1,10,20

D.
TestKing1(config-if)# switchport trunk encapsulation dot1q
TestKing1(config-if)# switchport mode dynamic desirable
TestKing1(config-if)# switchport trunk native vlan 10

E.
TestKing1(config-if)# switchport trunk encapsulation dot1q
TestKing1(config-if)# switchport mode dynamic desirable
TestKing1(config-if)# switchport trunk native vlan 10
TestKing1(config-if)# switchport trunk allowed vlan 1,10,20

Explanation:

The IEEE 802.1Q protocol can also carry VLAN associations over trunk links. However, this frame identification method is standardized, allowing VLAN trunks to exist and operate between equipment from multiple vendors.
In particular, the IEEE 802.1Q standard defines an architecture for VLAN use, services provided with VLANs, and protocols and algorithms used to provide VLAN services. Like Cisco ISL, IEEE 802.1Q can be used for VLAN identification with Ethernet trunks. Instead of encapsulating each frame with a VLAN ID header and trailer, 802.1Q embeds its tagging information within the Layer 2 frame. This method is referred to as single-tagging or internal tagging.
802.1Q also introduces the concept of a native VLAN on a trunk. Frames belonging to this VLAN are not encapsulated with any tagging information. In the event that an end station is connected to an 802.1Q trunk link, the end station can receive and understand only the native VLAN frames. This provides a simple way to offer full trunk encapsulation to the devices that can understand it, while giving normal access stations some inherent connectivity over the trunk.

You can manually configure trunk links on Catalyst switches for either ISL or 802.1Q mode. In addition, Cisco has implemented a proprietary, point-to-point protocol called Dynamic Trunking Protocol (DTP) that negotiates a common trunking mode between two switches. The negotiation covers the encapsulation (ISL or 802.1Q) as well as whether the link becomes a trunk at all.

In the switchport mode command, you can set the trunking mode to any of the following:
1. trunk-This setting places the port in permanent trunking mode. The corresponding switch port at the other end of the trunk should be similarly configured because negotiation is not allowed. You should also manually configure the encapsulation mode.
2. dynamic desirable (the default)-The port actively attempts to convert the link into trunking mode. If the far-end switch port is configured to trunk, dynamic desirable, or dynamic auto mode, trunking is successfully negotiated.
3. dynamic auto-The port converts the link into trunking mode. If the far-end switch port is configured to trunk or dynamic desirable, trunking is negotiated. Because of the passive negotiation behavior, the link never becomes a trunk if both ends of the link are left to the dynamic auto default. 802.1Q also introduces the concept of a native VLAN on a trunk. Frames belonging to this VLAN are not encapsulated with any tagging information. In the event that an end station is connected to an 802.1Q trunk link, the end station can receive and understand only the native VLAN frames. This provides a simple way to offer full trunk encapsulation to the devices that can understand it, while giving normal access stations some inherent connectivity over the trunk.
switchport trunk allowed vlan, defines which VLANs can be trunked over the link. By default, a switch transports all active VLANs (1 to 4094) over a trunk link. There might be times when the trunk link should not carry all VLANs. For example, broadcasts are forwarded to every switch port on a VLAN-including the trunk link because it, too, is a member of the VLAN. If the VLAN does not extend past the far end of the trunk link, propagating broadcasts across the trunk makes no sense.