This involves a sentence that contains a linking verb like any form of the verb “to be”, “become”, “seem,” “appear,” “feel”, etc.

Examples:

You look marvelous. (marvelous further describes or complements the subject “you.”)

The homemade chili smells delicious. (delicious further describes or complements the chili)

He is a television producer. (producer further tells you something about “he”)

Sadly, only B looks correct… C. If ‘Neither’ is the subject, it takes a singular verb, but in this case the subject includes Carol/her children. Neither Carol nor her children ARE coming… “When a singular and plural subject are connected by either/or or neither/nor, put the plural subject last and use a plural verb.” D. is obvious (MANY people is plural, IS should be ARE) A. is obvious, the SOUND (of the waves) IS drowning out… ……& the reason B is correct = ” When I is one of the two subjects connected by either/or or neither/nor, put it second and follow it with the singular verb am.”