A 90-year-old nursing home resident presents with confusion and a cough after several days of complaining of being weak. She is bedridden, has numerous medical conditions, and takes a variety of medications. Your assessment reveals that her temperature is 99.0°F, her skin is cool and dry, her blood pressure is 118/66 mm Hg, and her heart rate is 68 beats/min and regular. She is not experiencing obvious respiratory distress, and her oxygen saturation is 93% on room air. This patient is MOST likely experiencing:

A) pneumonia.
B) heart failure.
C) hypoglycemia.
D) a pulmonary embolism.

Ans: A) pneumonia.