Answer:
D. Testosterone
Explanation:
Gynecomastia states the condition of enlargement or swelling of breast tissue in the male body. It happens because of the high level of estrogen or low-level of testosterone. Testosterone hormone controls male characteristics whereas estrogen hormone controls female characteristics. Breast enlargement happens to men when they cross 50. One-fourth of the men suffer from low estrogen after their 50's because when male cross 50, testosterone level starts to drop, and as a result, they have breast enlargement problems.