**Core Concept**
The Spetzler Martin Grading System is used to predict the risk of surgical treatment for arteriovenous malformations (AVMs). It takes into account the size of the AVM, its location, and the presence of deep venous drainage.

**Why the Correct Answer is Right**
The system assigns points as follows: size (1-3 points), location (0-1 point for eloquent areas like the internal capsule), and deep venous drainage (1 point). For an AVM of size 3-6 cm (medium size), it would typically receive 2 points for size, 1 point for deep venous drainage, and 1 point for location near the internal capsule, totaling 4 points, but given the size range provided (3-6 mm), this would be considered small, thus scoring 1 for size.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it underestimates the risk associated with the location and deep drainage.
**Option B:** Incorrect as it doesn't accurately reflect the points for size, location, and drainage.
**Option C:** Incorrect because, although the size is small (which would score 1 point), the combination of deep venous drainage and location near the internal capsule increases the risk.
**Option D:** Incorrect as it overestimates the points, particularly for the size which is less than what would be expected for higher scores.

**Clinical Pearl / High-Yield Fact**
The Spetzler Martin Grade is crucial in planning the treatment of AVMs, as it helps predict the surgical risk. A higher grade indicates a higher risk of surgical complications.

**Correct Answer:** Correct Answer: C. 3