Which of the Following Is the Best Example of the Foot-In-The-Door

Which of the following is the best example of the foot-in-the-door technique of persuasion?

A) anti-smoking advertisements that rely on celebrity spokespeople advocating for reduction in cigarette use
B) anti-smoking advertisements that use charts and graphs to show how many people die from smoking-related causes each year
C) getting your parents to agree to cut their smoking down by a few cigarettes, then asking them to quit altogether
D) supporting your sister who has decided to go cold turkey in order to quit smoking