**Core Concept**
The question is testing the student's knowledge of medications with dual efficacy in treating psychiatric disorders, specifically their ability to exhibit both antidepressant and antipsychotic properties. This concept is relevant to the treatment of conditions like bipolar disorder, where patients may require a medication that can manage both depressive and manic episodes.

**Why the Correct Answer is Right**
The correct answer is a medication that acts on multiple neurotransmitter systems, including serotonin and dopamine, to produce its antidepressant and antipsychotic effects. This is often achieved through a combination of blockade of serotonin and dopamine receptors, which helps to stabilize mood and reduce symptoms of psychosis. Specifically, the correct answer is a type of medication known as an atypical antipsychotic, which is characterized by its ability to block both serotonin and dopamine receptors.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not have a well-established mechanism of action for antidepressant effects.
**Option B:** This option is incorrect because it is primarily used as an antihistamine and does not have a significant impact on the neurotransmitter systems involved in mood regulation.
**Option C:** This option is incorrect because it is primarily used as a mood stabilizer and does not have significant antipsychotic effects.

**Clinical Pearl / High-Yield Fact**
When choosing a medication for a patient with bipolar disorder, it's essential to consider the medication's potential to induce weight gain, metabolic changes, and other side effects. Atypical antipsychotics like the correct answer can be effective but require careful monitoring of these potential issues.

**Correct Answer: C. Clozapine.**