How do TCP and UDP differ in the way they guarantee packet delivery?
A . TCP uses checksum, acknowledgement, and retransmissions, and UDP uses checksums only.
B . TCP uses retransmissions, acknowledgement and parity checks and UDP uses cyclic redundancy checks only.
C . TCP uses checksum, parity checks, and retransmissions, and UDP uses acknowledgements only.
D . TCP uses two-dimensional parity checks, checksums, and cyclic redundancy checks and UDP uses retransmissions only.
Answer: A