The Underlying Basis of the Insanity Defense Is

The underlying basis of the insanity defense is

A) some people who have a mental illness are not able to fully comprehend their behavior, so are not able to form the needed intent for a crime, and thus shouldn't be punished.
B) people who have a mental illness cannot ever form the intent needed to commit a crime, so shouldn't be punished.
C) even if they had the required intent for a crime, the mentally ill still shouldn't be punished.
D) people who have a mental illness should not be punished.