Kurt Lewin Attempted to Convince People to Switch from Eating

Kurt Lewin attempted to convince people to switch from eating white bread to eating wheat bread. When participants were asked to make a public commitment, he found that:

A) participants refused to eat wheat bread when the commitment was public rather than private.
B) participants continued to eat white bread when the commitment was in writing rather than verbal.
C) participants continued to eat the bread they preferred prior to the study.
D) participants displayed a stronger commitment to the change to wheat bread.