**Core Concept**
The question is testing the knowledge of a specific antidote for benzodiazepines, which are a class of psychoactive drugs used to treat anxiety disorders, insomnia, and seizures. The correct antidote should be able to reverse the effects of benzodiazepines by inhibiting their action at the GABA_A receptor.

**Why the Correct Answer is Right**
Flumazenil is a specific antidote for benzodiazepines, including Restyl (Alprazolam). It works by competitively inhibiting the action of benzodiazepines at the GABA_A receptor, thereby reversing their sedative, anxiolytic, and muscle relaxant effects. Flumazenil has a high affinity for the benzodiazepine recognition site on the GABA_A receptor, which allows it to effectively counteract the effects of benzodiazepines.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a known antidote for benzodiazepines.
**Option B:** This option is incorrect because it is a benzodiazepine itself and would only exacerbate the effects of Restyl/Alprazolam.
**Option C:** This option is incorrect because it is not a specific antidote for benzodiazepines and may actually worsen the situation.

**Clinical Pearl / High-Yield Fact**
It is essential to note that flumazenil should be used with caution, as it can precipitate seizures in individuals with a history of seizure disorders. Additionally, flumazenil should only be administered in a setting where benzodiazepine overdose can be closely monitored.

**Correct Answer: D. Flumazenil**