Linda is in good health, but she has become convinced that her headache is a sign that she has brain cancer. Linda is most likely suffering from
A. a conversion disorder
B. post-traumatic stress disorder
C. hypochondriasis
D. an obsessive-compulsive disorder
(this is for psychology btw)

C. hypochondriasis

Explanation:

Hypochondriasis is also known as illness anxiety disorder. This is a mental disorder in which an individual develops intense fear and undue anxiety of having a serious health condition, when in actual fact, there are no visible medical tests or diagnosis that indicates the person has such serious ailment they are afraid they possess.

This mental disorder usually arises when the individual associates a little sensation such as headache, to having a serious medical condition such as brain cancer.

Thus, Linda can be said to be suffering from hypochondriasis. She's having excessive fear and anxiety of having brain cancer which does not exist.