Donny's non-profit organization mailed out small pins with their symbol on them to people in the community two weeks before they went door to door asking for donations. They noticed that the people who had the pins on when they answered their door were more likely to give a donation. An explanation for this, according to social psychologists, would be: a. Once someone has agreed to give a small donation, they are more likely to give a larger one.
b. Once someone has made a commitment, or taken a position on an issue, they are more likely to make other commitments that are consistent with our first one.
c. Donny is annoying people during dinner by knocking on their doors, so to get rid of them they gave them a donation.

b. Once someone has made a commitment, or taken a position on an issue, they are more likely to make other commitments that are consistent with our first one

Explanation:

Social psychology, through the Theory of Reasoned Action and the Theory of Planned Behavior, suggest that personal traits and past behavior can be used to predict future behavior. People who have taken a position in a subject, like those who decided to wear the pin, probably tend to help others and apply their moral responsibility to charitable giving.

Option a. is incorrect because the example doesn´t describe people that have already agreed to give a small donation. Option c. is incorrect because the example doesn´t provide any information about the time Donny was going door to door, so we don´t know if him going at dinner time was a factor.