Useful therapy for improving fertility

Useful therapy for improving fertility in polycystic ovarian syndrome (PCOS) includes which of the
following?

Cyproterone acetate
Ethinyloestradiol
Glibenclamide
Metformin  This is the correct answer
Spironolactone

Metformin has been shown to increase the rate of conception in PCOS through improved insulin
sensitivity (although studies have not been powered to show a significant impact on pregnancy
outcome).
Ethinyloestradiol and cyproterone acetate combine to form Dianette the oral contraceptive.
Cyproterone acetate is also used as an anti-androgen for hormonal treatment of prostatic carcinoma.
Spironolactone is used for hirsutism but is teratogenic.
Glibenclamide is not used in PCOs.