Marcia values the opinions and desires of both her parents and her close friends. When she's with her parents, she finds herself agreeing with them. When she's with her friends, she finds herself agreeing with them, even though they sometimes disagree with her parents.
This change in Marcia's behavior represents the influence of Bibb Latané's (1981) concept of on normative conformity.

a) number
b) immediacy
c) pressure
d) strength

(B) Immediacy

Explanation:

 The normative conformity is one of the type of conformity psychological  concept in which the person wants to change their behavior, thoughts values and the attitude so that they are liked by others or due to some peer pressure.  

 According to the given question, the change occur in the Marcia's behavior is due to the influence Bibb Latané's concept of immediate on the normative conformity.

 This type of concept is basically explain about the social influence on the life of an individual person as she values both her parents and friends opinions. Therefore, Option (B) is correct answer.