Which one of these statements could be a possible reason?

Refer to the exhibit. You are setting up a 2-gigabit EtherChannel. Following IEEE standards, the
exhibit shows your configuration in a local switchl. However, EtherChannel is not coming up.
Which one of these statements could be a possible reason?

A.
EtherChannel is only available in Cisco equipment.

B.
The customer side is supposed to be running PAgP, which is a Cisco standard.

C.
PAgP is not an IEEE standard. VRRP should be used.

D.
The configuration on switch1 needs to be modified to use LACP.

Explanation:
Background Theory
LACP trunking supports four modes of operation, as follows:
On: The link aggregation is forced to be formed without any LACP negotiation .In other words, the
switch will neither send the LACP packet nor process any incoming LACP packet. This is similar to
the on state for PAgP.
Off: The link aggregation will not be formed. We do not send or understand the LACP packet. This
is similar to the off state for PAgP.
Passive: The switch does not initiate the channel, but does understand incoming LACP packets.
The peer (in active state) initiates negotiation (by sending out an LACP packet) which we receive
and reply to, eventually forming the aggregation channel with the peer. This is similar to the auto
mode in PAgP.
Active: We are willing to form an aggregate link, and initiate the negotiation. The link aggregate will
be formed if the other end is running in LACP active or passive mode. This is similar to the

desirable mode of PAgP.
There are only three valid combinations to run the LACP link aggregate, as follows:

Note: By default, when an LACP channel is configured, the LACP channel mode is passive.
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