The Night Nurse Is Reviewing the Vital Signs of a Client

The night nurse is reviewing the vital signs of a client in an extended care facility. The nurse notes the client's oral temperature at 6 a.m. was 98.0°F, but that evening, the client's oral temperature was 99.2°F. What is this variation indicative of?

A) The client's temperature has been improperly assessed either in the morning or evening; the nurse can't be sure which.
B) The client is developing an infection.
C) The client is experiencing stress.
D) The client's temperature is demonstrating diurnal variations.