Which field is common to all extension headers in IPv6?

A.
The protocol field

B.
The Next Header field

C.
The Type of service field

D.
The Hop Limit field

Explanation:
The following table should be memorized, these are the code mappings.
As you can see, these codes are specified in the Next Header Field.
Incorrect Answers:
A: The protocol field was renamed to the Next Header field. It does not exist as a field in Ipv6.
C: The type of service field, which was a field n Ipv4, was removed and does not exist in Ipv6.
D: The hop limit field was formerly known as the TTL field. Although this field does exist in Ipv6, it
is not common to the extension headers.