A Friend Asks Me to Do Him a Favor and Pick

A friend asks me to do him a favor and pick up his wife's birthday gift. I agree. Just as I am about to leave, he says, "Since you are going to be passing by the florist anyway, would you mind also picking up some red roses for me? I agree. This exemplifies which of the following?

A) the door-in-the-face technique
B) the foot-in-the-door-technique
C) low balling
D) over the top technique