A nurse is providing discharge teaching to a client who has a new prescription for insulin. Which of the following instructions should the nurse include?

Choice A reason: Storing unopened insulin in the freezer can degrade it. Refrigeration is correct, keeping insulin stable, making freezing incorrect for proper storage instructions. Choice B reason: Rotating injection sites prevents lipodystrophy (tissue changes) by avoiding repeated trauma. This ensures consistent absorption, making it a critical instruction for insulin administration. Choice C reason: Shaking insulin vials can damage proteins or create air bubbles, affecting efficacy. Gentle rolling is recommended for cloudy insulin, making this incorrect for proper handling. Choice D reason: A 30-degree angle is too shallow for subcutaneous insulin; a 45–90-degree angle is standard. This incorrect technique may affect absorption, making it wrong.