In Sheehan's syndrome:

Correct Answer: C

Rationale: Sheehan's syndrome (pituitary necrosis) causes low metabolic rate and low I^131 uptake from secondary hypothyroidism.

Correct Answer: C

Rationale: Primary aldosteronism causes hypokalemia from potassium wasting.

Correct Answer: D

Rationale: Addison's disease features skin hyperpigmentation from ACTH excess.

Correct Answer: A

Rationale: Hyperthyroidism features warm, moist skin, fine tremor, and atrial fibrillation.

Correct Answer: A

Rationale: High fasting insulin with hypoglycemia is highly specific for insulinoma.