61. If I ___ known, I would have come. a) have b) had c) would have d) was

Перевод задания: Если бы я знал(а), я бы пришёл(пришла).

Это условное предложение третьего типа: If + Past Perfect → would have + V³. Поэтому: had known.

Ответ: b) had