Mouse Mutations Can Affect an Animal's Appetite and Eating Habits

Mouse mutations can affect an animal's appetite and eating habits.The ob gene codes for a satiety factor,the hormone leptin.The db gene product,the leptin receptor,is required to respond to the satiety factor.
-Leptin is a product of adipose cells.Therefore,a very obese mouse would be expected to have

A) increased gene expression of ob and decreased expression of db.
B) increased gene expression of db and decreased expression of ob.
C) decreased transcription of both ob and db.
D) mutation of ob or db.
E) same levels of transcription and non-obese mice