Answer:
The answer is: b) door-in-the-face.
The-door-in-the-face technique is a compliance method frequently explored by social psychologists.
By using this technique, person A attempts to convince person B to do something. Person A first makes a large request, assuming that person B will probably not accept it. Metaphorically, person B's refusal represents slamming of a door in person A's face. Person A then makes a smaller request (in this case trip to the zoo), convinced that person B will accept it, having a guilty conscience.