**Core Concept**
The question tests the student's knowledge of antiepileptic medications used in specific types of epilepsy. Petit mal epilepsy, also known as absence seizures, is a condition characterized by brief, sudden lapses in consciousness. The underlying principle being tested is the pharmacological treatment of epilepsy.

**Why the Correct Answer is Right**
The correct answer is a medication that acts on the GABAergic system, enhancing inhibitory neurotransmission to reduce the risk of seizures. It is a first-line treatment for absence seizures and has a rapid onset of action. This medication is often used in conjunction with other antiepileptic drugs to control seizures and minimize side effects.

**Why Each Wrong Option is Incorrect**
**Option A:** This medication is actually used to treat bipolar disorder and major depressive disorder, not epilepsy. It is a mood stabilizer that affects the activity of sodium channels and has a different mechanism of action compared to the correct answer.
**Option B:** This medication is used to treat various types of seizures, including tonic-clonic and partial seizures, but it is not the first-line treatment for absence seizures. It has a different mechanism of action, affecting the activity of sodium channels and calcium channels.
**Option C:** This medication is used to treat a range of conditions, including anxiety disorders, insomnia, and seizures, but it is not the primary treatment for absence seizures. It has a different mechanism of action, affecting the activity of GABA receptors.

**Clinical Pearl / High-Yield Fact**
The correct answer is a classic example of a medication that acts on the GABAergic system to treat absence seizures. This medication is often used in combination with other antiepileptic drugs to minimize side effects and maximize efficacy.

**Correct Answer: C. Ethosuximide**