Ahistorical novel is
a. the same as a memoir
b. the same as a biography
c. the same as an autobiography
d. none of the above

A historical novel is simply a novel written a long time ago.  Since it is not limited to a memoir, a biography, or an autobiography, your answer is D.  

Historical novel, a novel that has as its setting a period of history and that attempts to convey the spirit, manners, and social conditions of a past age with realistic detail and fidelity  to historical factI'm thinking the answer may be B.

Hope this helps