A Treatment Condition in Seligman Et Al

A treatment condition in Seligman et al.'s (2005) happiness intervention asked participants to write down three things that went well each day and their causes every night for one week.What were the results of this treatment group?

A) Participants showed an increase in happiness after the exercise but returned to their pre-test levels of happiness at the three month post-test.
B) Participants showed an increase in happiness after the exercise that was sustained at the six-month post-test.
C) Participants showed increased happiness immediately after the exercise but no long-term effects.
D) Participants did not show any increase in happiness.