**Core Concept**
Free radicals play a significant role in the development of cataracts by causing oxidative stress and lens opacity. Preventing lens opacity by scavenging free radicals is a crucial aspect of maintaining lens transparency.

**Why the Correct Answer is Right**
Free radical scavengers, such as antioxidants, can neutralize free radicals and prevent oxidative stress. The correct answer is a type of antioxidant that has been shown to prevent lens opacity by scavenging free radicals. This is achieved through the neutralization of reactive oxygen species (ROS) and other free radicals that contribute to cataract formation. The antioxidant works by donating electrons to stabilize free radicals, thereby preventing them from causing damage to the lens.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a well-known antioxidant that prevents lens opacity. The mechanism of action is not well understood, and it is not a commonly recommended treatment for cataract prevention.

**Option B:** This option is incorrect because it is a type of medication that is used to treat glaucoma, not cataracts. While it may have some antioxidant properties, it is not specifically indicated for preventing lens opacity.

**Option C:** This option is incorrect because it is a type of antioxidant that primarily has anti-inflammatory properties, rather than free radical scavenging properties. While it may have some benefits for overall eye health, it is not specifically indicated for preventing lens opacity.

**Clinical Pearl / High-Yield Fact**
Vitamin C and E are two well-known antioxidants that have been shown to prevent lens opacity by scavenging free radicals. These vitamins can be found in various foods, including fruits and vegetables, and can also be taken as supplements.

**Correct Answer:** C. N-Acetylcarnosine