What Lead to the Glutamate Hypothesis of Schizophrenia

What lead to the glutamate hypothesis of schizophrenia?

A) Phencyclidine-like drugs, which enhance glutamate neurotransmission, cause schizophrenia-like symptoms.
B) Phencyclidine-like drugs, which disrupt glutamate neurotransmission, cause schizophrenia-like symptoms.
C) Research indicates that schizophrenic patients often abuse phencyclidine-like drugs because it leads to increased glutamate levels.
D) Research indicates that schizophrenic patients often abuse phencyclidine-like drugs because it leads to decreased glutamate levels.