Step 1: The triad of hirsutism (excess male pattern hair), oligo or amenorrhoea (menstrual irregularity) and obesity in a reproductive age woman is the classic picture of polycystic ovarian disease or syndrome.
Step 2: PCOD reflects hyperandrogenism plus chronic anovulation, often with insulin resistance, producing exactly these clinical and biochemical features, so option (a) is correct.
Step 3: An androgen secreting ovarian tumour (b) would cause rapidly progressive virilisation with markedly high testosterone and is far less common than PCOD for this slow indolent presentation.
Step 4: Androgen insensitivity syndrome (c) occurs in a genetically male individual who is phenotypically female with absent body hair, the opposite of hirsutism, while Turner syndrome (d) features short stature and primary amenorrhoea from gonadal dysgenesis without hyperandrogenism.