Which of the following insulins can be administered intravenously?

Correct Answer: A

Rationale: Only regular insulin is soluble and safe for IV administration.

Correct Answer: B

Rationale: Chronic corticosteroids cause infections, hypertension, cataracts, and myopathy. They cause hypokalaemia, not hyperkalaemia.

Correct Answer: A

Rationale: Free T4 provides negative feedback to inhibit TSH secretion.

Correct Answer: D

Rationale: The average dose for healthy adults is 100-200 μg/day, typically 1.6 μg/kg.

Correct Answer: C

Rationale: Carbimazole inhibits thyroid hormone synthesis, has an active metabolite (methimazole), and can cause neutropenia. It doesn't block T4 to T3 conversion, and rash management varies.