Which type of persuasion involves encouraging a person to agree to a small favor or to buy a small item

Foot-in-the door mechanism

Explanation:

Foot in the door technique is the mechanism in which a person tends to persuade other through making a small request or asking for small favor first.If the person agrees for fulfilling small request then requester moves on for large request.

This is an tactical approach for making a person agree on large intended  request after succeeding from convincing them for agreeing on small favor.

Example-asking for small amount of money for need and later borrowing more money from parents .

answer; knowledge,reason,and judgement;