Step 1: Concept
Absence seizures (petit mal) are characterized by brief, sudden lapses of consciousness. Specific anticonvulsants are required to target the T-type calcium channels involved.
Step 2: Meaning
The "drug of choice" is the medication that provides the best balance of efficacy and safety for a specific condition.
Step 3: Analysis
Carbamazepine and Phenytoin can actually worsen absence seizures. Ethosuximide is a drug of choice for pure absence seizures, but Sodium valproate is the preferred first-line choice, especially if the patient has mixed seizure types.
Step 4: Conclusion
Sodium valproate is the correct drug of choice among the options.
Final Answer: (D)