A nurse is teaching the parents of a child who is to start using a metered-dose inhaler (MDI) to treat asthma. Which of the following information should the nurse include in the teaching?

A. This statement is incorrect; the spacer does not primarily increase medication delivery to the oropharynx. B. The spacer helps to increase the amount of medication that reaches the lungs by allowing larger particles to settle out and preventing them from being deposited in the mouth and throat. C. Inhaling slowly and deeply is recommended for effective medication delivery when using an MDI with a spacer. D. Covering the exhalation slots would prevent proper airflow and could cause the child to inhale exhaled air, which is not recommended during inhalation.