How does forced expiration differ from quiet expiration in terms of muscle involvement?

• A. Quiet expiration requires active contraction of the diaphragm.
• B. In quiet expiration, additional muscles like the sternocleidomastoid are involved.
• C. Forced expiration involves the active contraction of abdominal and internal intercostal muscles.
• D. Forced expiration relies solely on the elastic recoil of the lungs.

Answer: (C)