Answer: Foot in the door
Step-by-step explanation:
A. In Ingratiation one tries to influence the respondent by using flattery or compliments etc.
B. In Door-in-the-Face technique the influencer first make a big request followed by a small one that the respondent will most likely accept.
C. In need satisfaction the influencer first try to understand the needs of the respondent and then make his move as per the observations made.
D. In foot in the door first a small request is made which the respondent will most likely accept and then the crucial request is presented before the respondent.
E. In Adaptive Selling the technique of changing behavior is used as per the changing requirements.
Hence, from the above we can conclude that Charlotte used foot in the door.