**Core Concept**
The patient's presentation of a manic episode in the past and current symptoms of depressed mood, anhedonia, and psychomotor retardation is suggestive of a bipolar disorder, specifically a depressive episode. Management of bipolar depression requires a combination of treatments that address the depressive symptoms while minimizing the risk of inducing mania or hypomania.

**Why the Correct Answer is Right**
In bipolar depression, the addition of a mood stabilizer or an atypical antipsychotic to an antidepressant can help reduce the risk of inducing mania or hypomania. This combination can also enhance the effectiveness of the antidepressant. Lithium is a classic mood stabilizer that has been shown to be effective in treating bipolar depression. Aripiprazole is an atypical antipsychotic that has a unique mechanism of action, acting as a partial agonist at the dopamine D2 and serotonin 5-HT1A receptors, which can help mitigate the risk of inducing mania.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because a single antidepressant may not be sufficient to manage bipolar depression, and it may increase the risk of inducing mania or hypomania.
* **Option B:** This option is incorrect because a benzodiazepine may provide temporary relief from symptoms but does not address the underlying mood disorder and can lead to dependence and withdrawal symptoms.
* **Option C:** This option is incorrect because a non-selective beta-blocker may provide some relief from symptoms of anxiety and tremors but does not address the underlying mood disorder.

**Clinical Pearl / High-Yield Fact**
A mnemonic to remember the key components of managing bipolar depression is "MADDS": Mood stabilizer (e.g., lithium), Antidepressant (e.g., selective serotonin reuptake inhibitor), Dose adjustment (of the antidepressant), and Dose monitoring (of the mood stabilizer).

**Correct Answer: C. Lithium + Aripiprazole.**