Which subjective assessment data supports the nurse's conclusion that a client is experiencing orthopnea?

A. "I sleep on three pillows at night." Orthopnea is difficulty breathing while lying flat, which improves when the client sits up or uses multiple pillows to elevate their head. This statement strongly suggests orthopnea, a common symptom in conditions like heart failure. B. "I cough a lot at night and it keeps me up half the night." Nocturnal coughing can be related to conditions such as gastroesophageal reflux disease (GERD), postnasal drip, or respiratory infections, but it is not the defining symptom of orthopnea. C. "It doesn't take much activity before I'm out of breath." This statement describes dyspnea on exertion, which is common in heart and lung diseases but differs from orthopnea, which specifically occurs when lying flat. D. "I have multiple attacks of wheezing almost daily." Frequent wheezing is typically associated with asthma or chronic obstructive pulmonary disease (COPD) rather than orthopnea. Orthopnea is related to fluid redistribution when lying down rather than airway constriction.