A 12-mo-old toddler is brought to the ER with a very high fever. The mother became concerned when the fever did not subside after 48 hours and a bright red rash appeared. The infant was admitted to observation to monitor the fever and provide rehydration. When the toddler cried, the nurse picked her up to comfort and noticed the rash would subside if pressure was applied. Not surprisingly, the fever broke the next day and the girl recovered without incident. The cause of the patient's disease was:

A) German measles (rubeola)
B) Varicella-Zoster virus
C) Human Herpesvirus 6 or 7
D) Staphylococcus aureus