The answer is
letter C.
Encephalitis is
a disease in which the brain swells causing edema and eventually the
destruction of nerve cells within the brain. It is a very rare condition that
often occurs in the year of life but it eventually decreases with age. Older
adults and very young groups are most likely to have a severe case of
encephalitis. This disease is often caused by a viral infection that can occur
through contaminated food, mosquito or insect bites, breathing in contaminated
air, and possibly skin contact.