An 88-year-old resident of a long-term care home has been suffering from a 3-day onset of increased ...

An 88-year-old resident of a long-term care home has been suffering from a 3-day onset of increased shortness of breath and decreased oxygen saturation.
 
  At the hospital, an anterior-posterior chest x-ray and sputum culture and sensitivity have confirmed a diagnosis of bacterial pneumonia, yet the client's tympanic temperature has not exceeded 37.3 C (99.2 F). The health care team would recognize that which of the following phenomena likely underlies this situation?
  A)
  An older adult is often insensitive to exogenous pyrogens.
  B)
  An older adult is sometimes incapable of vasodilation.
  C)
  An older adult's hypothalamus has diminished thermoregulatory ability.
  D)
  Infections manifest by cognitive changes in older adults.