After spending two years of tedious work fixing up an old house themselves, Abby and Brian are even more convinced that they made the right choice to buy the place. Their feelings are an example of a....

After spending two years of tedious work fixing up an old house themselves, Abby and Brian are even more convinced that they made the right choice to buy the place. Their feelings are an example of

a. counterattitudinal advocacy.

 b. insufficient punishment.

c. the Ben Franklin effect.

d. justifying their effort.