Step 1: Metformin is a biguanide oral antidiabetic. It suppresses hepatic gluconeogenesis, enhances insulin-mediated glucose uptake in muscle and fat, slows intestinal glucose absorption and promotes peripheral glucose utilisation. It is a mainstay drug for type 2 diabetes mellitus, so option (a) is true.
Step 2: Because it reduces insulin resistance and hyperinsulinaemia, metformin is also widely used in polycystic ovarian disease to restore ovulation and improve metabolic parameters. So option (b) is also true.
Step 3: Metformin is not a treatment for pregnancy induced hypertension, so option (c) is wrong. Since both diabetes and PCOD are valid indications, the best answer is option (d), both a and b.