Answer:
A. The growing number of Anglo-Indian marriages.
Step-by-step explanation:
During the period of settlement, many white settlers interacted with people from indian communities and fell in love with them.
At that time, the puritans saw this as a problem (since the natives held a different religion than the majority of the settlers). They established half-way covenant as a way to convert the indians and the children that born from the mixed relationship into their religion.