Final answer:
The antipsychotic that is a partial D2 receptor agonist is Aripiprazole. It acts by partially stimulating the D2 receptors, which can help in treating schizophrenia with fewer side effects.
Step-by-step explanation:
The antipsychotic that is a partial D2 receptor agonist among the options is D. Aripiprazole. Aripiprazole works uniquely compared to the traditional antipsychotics, as instead of only blocking dopamine receptors, it partially stimulates the D2 receptors. This action helps in balancing the levels of dopamine in the brain, which is beneficial in treating the symptoms of schizophrenia and other psychoses while causing fewer side effects typically associated with dopamine antagonists.