All are causes of Gynaecomastia, except
Even androgen therapy can cause gynecomastia but among all options given in the question, the best answer is androgen therapy.
Some important causes of Gynaecomastia

Leprosy  
Testicular tumours   

Lung cancer - Small cell type 

Adrenal disease  
Liver disease
Hyperthyroidism 
Hyperprolactinemia  
Castration     
Orchitis         

Drugs -

Digitalis  
Spironolactone   
Cimetidine      
Clomiphene      
Methyldopa 
Androgens  
Gonadotrophins  
Estrogens 
Progesterones   
Ketoconazole.                                                                                                                                           

Gynecomastia refers to the enlargement of the male breast
Hormone effects

Like the female breast, the male breast is also subject to hormonal influences, and gynecomastia occurs as a result of an imbalance between estrogens which stimulate breast tissue and androgens which counteract these effects.
Usually, gynecomastia is caused by an estrogen excess and is usually the result of an increased estrogen/androgen ratio, caused by -
Increased estrogen
Decreased androgen
hCG producing tumours (hCG stimulates Leydig cells to produce estrogen).
Cimetidine therapy
Androgen therapy
Leprosy
Small cell carcinoma lung