Why was the Header Length field omitted from IPv6?

A.
IPv6 made it an option

B.
The IPv6 header is fixed as 40 Bytes

C.
IPv6 renamed it the Payload Length field

D.
The IPv6 header is fixed as 20 bytes with options

Explanation:
The Ipv6 header is fixed at 40 bytes, also called 40 octets (8 bit units). Some questions will ask
this in bits, which would be (40 x 8 = 160) 160 Bits.
Incorrect Answers:
A: The header does not specify or control the size of the header, the header is of fixed length.
C: The header does not specify or control the size of the header, the header is of fixed length.
D: The Ipv6 header is fixed length, at 40 bytes. It is the IP4 header that is fixed as 20 bytes with
options.