TOEIC・English Undergraduate almost 2 yearsago

(7)の問題で3番が答えだと分かったのですが、 何故その他の3つの答えが不正解なのか文法事項を含めてできるだけ詳細に教えてほしいです。

(7) ( ) started raining the day before, the picnic was postponed. 1 Having 2 It has ③It having (8) How much did the digital camera ( )? 4 It