1. The interviews which is scheduled on the 15th of this month _______ , because our president has to go overseas factories urgently.
(A) postponed
(B) was postponed
(C) postponing
(D) will postpone
정답이 b라는데요...
그럼 주어인 The interviews가 단수라는 의미인데.....왜 단수인거죠??