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

A. Coughing at night could be indicative of conditions like asthma or heart failure but is not specifically associated with orthopnea. B. Shortness of breath with activity is more indicative of dyspnea on exertion. C. Orthopnea refers to difficulty breathing when lying flat, often relieved by propping up with pillows. A client using three pillows at night to sleep suggests they are managing orthopnea. D. Wheezing daily suggests a respiratory issue, possibly asthma, but does not directly indicate orthopnea.