Shouldn't all of the choices be the correct answer.
Portions of the frame control field as well as the sequence control field are also used to construct the AAD, according to page 85. FIGURE 3.9.
A and C are in gray, which is explained as "some fields used..." OK, but.that is not too clear. Maybe meant to be "sometimes fields are used..."?
OK, I see. RE: fig 3.9. the exploded Frame Control fields in gray should all be black to indicate they ARE used in the AAD, while the white ARE NOT.