At Her Counselor's Direction, Margaret Kept Track of the Good

At her counselor's direction, Margaret kept track of the good things in her life. Which of the following is MOST likely to be the result?

A) She will feel happier.
B) She is likely to maintain a daily list on her own.
C) She will have fewer depressive symptoms for up to 6 months after she stops making a list.
D) All of these are likely.