One of Your Friends Calls and Says That She Bought

One of your friends calls and says that she bought a new shelving unit for her garage. She then asks if you can come over and help her take the heavy box out of the back of her car. When you arrive, your friend also asks you to help put the shelving unit together and to find a space for it in her garage. What you thought would be a 5-minute trip has turned into a 2-hour long ordeal. You have just experienced the ___________ technique.

A) low-ball technique
B) social proof technique
C) foot-in-the-door technique
D) door-in-the-face technique