Two commonly used networking protocols are TCP and UPD. Which of the following correctly describes the two?

A.
TCP provides best-effort delivery, and UDP sets up a virtual connection with the destination.

B.
TCP provides more services and is more reliable in data transmission, whereas UDP takes less resources and overhead to transmit data.

C.
TCP provides more services and is more reliable, but UDP provides more security services.

D.
TCP is reliable, and UDP deals with flow control and ACKs.

Explanation:
B: Two main protocols within the TCP/IP stack work at the transport layer: TCP and UDP. TCP is a reliable and connection-oriented protocol, which means it ensures packets
are delivered to the destination computer. If a packet is lost during transmission, TCP has the ability to identify this issue and resend the lost or corrupted packet. TCP is referred
to as a connection-oriented protocol because, before any user data is actually sent, handshaking takes place between the two systems that want to communicate. Once the
handshaking completes successfully, a virtual connection is set up between the two systems. UDP is considered a connectionless protocol because it does not go through these
steps. Instead, UDP sends out messages without first contacting the destination computer and does not know whether the packets were received properly or dropped. TCP
provides a full-duplex, reliable communication mechanism, and if any packets are lost or damaged, they are re-sent; however, TCP requires a lot of system overhead when
compared to UDP. If a programmer knows data dropped during transmission is not detrimental to the application, he may choose to use UDP because it is faster and requires
fewer resources.
A is incorrect because the descriptions are backward. UDP is a connectionless protocol that does not send or receive acknowledgments when a datagram is received. It does
not ensure that data arrives at its destination. It provides best-effort delivery. TCP is a connection-oriented protocol; thus, it performs handshaking and develops a virtual
connection with the destination computer. It ensures data arrives at its destination.
C is incorrect because UDP does not provide security services. However, TCP is more reliable and provides more services than UDP. Unlike UDP, TCP ensures that packets
reach their destinations, returns ACKs when a packet is received, and is a reliable protocol. It supports flow and congestion control, and error detection and correction.
D is incorrect because the description of UDP describes TCP. UDP does not return ACKs and does not guarantee that a packet will reach its destination. It is an unreliable
protocol. Furthermore, the destination computer does not communicate back to the source computer about flow control through UDP.