A young man( 28 years old, obese) goes to the doctor complaining of tenderness around the chest and an increase in chest size not associated with working out. Doctors run several blood tests on him, and afterwards, diagnose him with gynecomastia. Which of the following markers (chemicals) in his blood will likely be high in his test?

a. Aldosterone
b. Testosterone
c. Insulin
d. Luteinizing hormone
e. Follicle stimulating hormone
f. Estrogen