What is the size of a point-to-point GRE header, and what is the protocol number at the IP layer? 

Answer options:

A. 8 bytes, and protocol number 74
B. 4 bytes, and protocol number 47
C. 2 bytes, and protocol number 71
D. 24 bytes, and protocol number 1
E. 8 bytes, and protocol number 47

B