Which of the Following Statements Counters the "Circumstantial Evidence" for the Dopamine

Which of the following statements counters the "circumstantial evidence" for the dopamine theory of schizophrenia?

A) Antipsychotic drugs (neuroleptics) act as dopamine agonists, increasing the amount of dopamine in the brain.
B) A significant number of people with schizophrenia are not helped by dopamine antagonists.
C) The drug L-dopa, a dopamine agonist, is used to treat schizophrenic symptoms in patients with Parkinson's disease so it cannot be used for schizophrenia.
D) Amphetamines, which activate dopamine, can lessen psychotic symptoms in people with schizophrenia.