A patient diagnosed with bipolar disorder is prescribed lithium carbonate. The order states to administer 300 mg orally three times a day. How many milligrams of lithium should be administered over 24 hours?

Choice A reason: Administering 300 mg three times daily equals 900 mg total (300 mg × 3 = 900 mg). Choice B reason: 300 mg represents only one dose, not the total for 24 hours. Choice C reason: 1200 mg would be 300 mg four times daily, which is more than prescribed. Choice D reason: 600 mg equals 300 mg twice daily, not the correct order.