The Discovery of the Relationship Between Syphilis and Paralytic Dementia

The discovery of the relationship between syphilis and paralytic dementia revealed that

A) a mental disorder turned out to have a physiological cause.
B) schizophrenia often co-occurred in patients with sexually transmitted infections like syphilis.
C) both sexually transmitted infections and mental disorders can have a common viral cause.
D) people with paralytic dementia tend to be promiscuous.