According to the Law of Diminishing Returns, the 9^th Person

According to the law of diminishing returns, the 9^th person to offer public agreement with a group's position exerts _______ social influence on individual group members compared to the 3^rd person to agree with the group position.

A) less
B) more
C) the same amount of
D) None of these; it depends on the nature of the issue being debated.