By 1642, all towns in the colony

By 1642, all towns in the colony of Massachusetts（ ）by law to have schools.

were required

required

was required

had required

因为后面有by，且是动作发出者，所以空格处应该选被动，不选BD，主语为all towns，为复数，所以选were，选A。句意：到1642年，法律要求马萨诸塞殖民地的所有城镇都拥有学校。