What treatment is likely to be of most benefit?

A 16-year-old Caucasian girl presented with a 4-year history of facial hair growth, acne and secondary amenorrhoea.

On examination, her body mass index was 20 kg/m2 (18C25). Her gums and palmar creases were pigmented. Facial hair was evident on her upper lip and chin, and terminal hair was evident on her chest and abdomen. Her FerrimanCGallwey score was 25. She had acne affecting her face and back.

Investigations:

serum dehydroepiandrosterone sulphate15 µmol/L (3C12)

serum androstenedione12.2 nmol/L (0.6C8.8)

serum 17-hydroxyprogesterone120 nmol/L (1C10)

serum testosterone6.0 nmol/L (0.5C3.0)

serum sex hormone binding globulin18 nmol/L (40C137)

What treatment is likely to be of most benefit?
A . cyproterone acetate
B . fludrocortisone
C . flutamide
D . hydrocortisone
E . metformin