Mark's Brother Invited Him to Go Fishing

Mark's brother invited him to go fishing.Mark went down to the dock and as he put his pole in the boat,his brother told him they had to wash down the boat and clean it at the end of the day.Later,Mark was asked for cost $200 in gas and fees.Mark's brother used

A) compliance.
B) the lowball technique.
C) the reciprocity norm.
D) the foot-in-the-door technique.