Jack Helps Jill Go Up a Hill to Fetch a Pail

Multiple Choice

Jack helps Jill go up a hill to fetch a pail of water.According to the reciprocity norm,what behaviors should we expect from Jill?

A) Jill will later help Jack fix his car.
B) Jill will help Jack only if she is feeling depressed.
C) Jill will help Jack only if she is feeling guilty about snubbing Miss Mary Mack.
D) Jill will help Jack only if he is biologically related to her.