What does the sentence "Well, l just did!" mean？A． I just did something for the b

What does the sentence "Well, l just did!" mean？

A． I just did something for the boy andhe would be happy.

B． I just bought a nice doll for myself and I would be happy.

C． I just bought a present for Grandma and she would be happy.

D． I just did something for the boy and it would make me happy.