Either Diane or her parents ------ going to pay the bill.
B
Correct answer
Explanation
With 'either/or', the verb agrees with the nearest subject. 'Her parents' is plural, so use 'are'. The sentence means either Diane (singular) or her parents (plural) will pay, and we match the verb to 'parents'. Option A ('is') would be correct if the order were reversed: 'Either her parents or Diane is going'.