D: she was pressured by others to behave that way.

    Incorrect.
Believing that others caused her to behave in a certain way is an example of an external attribution.  In this case, the perception is that others (an external force) are causing her behavior.  If we are using Heider's Naive Psychologist view of attribution, this is an example of an external unstable attribution.  It is external because others are causing the behavior, and it is unstable, because others may not always cause her to behave the same way.  For more information, see p. 80 in Myers and your lecture notes.