How Does Encapsulating Security Payload (ESP) in Transport Mode Affect

How does Encapsulating Security Payload (ESP) in transport mode affect in the Internet Protocol (IP) ?

A) Authenticates the IP payload and selected portions of the IP header
B) Encrypts and optionally authenticates the complete IP packet
C) Encrypts and optionally authenticates the IP header, but not the IP payload
D) Encrypts and optionally authenticates the IP payload, but not the IP header