Refer to the Figure

Refer to the figure.In an experiment to test the function of leptin in mice, parabiotic twins were created by surgically connecting the circulatory systems of a wild-type (WT) mouse with an obese mouse or a wild-type mouse.The obese mouse either lacked functional leptin (genotype ob/ob) or lacked the receptor for leptin (genotype db/db) .After allowing the mice to feed at will, they observed the results shown in the figure. It is most likely that

A) mouse 1 has a genotype of ob/ob.
B) mouse 1 is a wild-type mouse.
C) mouse 2 has a genotype of db/db.
D) mouse 2 could be wild-type or have a genotype of ob/ob.
E) mouse 3 has a genotype of db/db.