An Adult with Diabetes Receives 20 Units of Insulin Each

An adult with diabetes receives 20 units of insulin each morning and evening. How will the nurse teach the patient to administer the insulin?

A) "Use a 1-mL syringe and give 0.4 mL."
B) "Use a 5-mL syringe and give 0.40 mL."
C) "Use a tuberculin syringe and give 4/10 mL."
D) "Use an insulin syringe and give 20 units."