Isen, Clark, and Schwartz (1976) Had a Confederate, Who Supposedly

Isen, Clark, and Schwartz (1976) had a confederate, who supposedly spent her last dime on a wrong number, call people who had received a free sample of stationery 0 to 20 minutes earlier. The results indicate these people's willingness to relay the phone message rose during the 5 minutes afterwards. Then, their helpfulness

A) dropped; as good mood wore off, so did their helpfulness.
B) increased.
C) both A and B.
D) none of these choices.