**Core Concept**
The permanent maxillary canine is a key tooth in the human dentition, characterized by its unique morphology and size. Understanding the dimensions of this tooth is crucial for dental professionals, particularly in the fields of orthodontics, restorative dentistry, and oral surgery.

**Why the Correct Answer is Right**
The permanent maxillary canine is generally wider mesiodistally than the other incisors and canines. This is due to the unique morphology of the tooth, which has a more pronounced cusp and a larger occlusal surface. The mesiodistal diameter of the crown is a critical measurement in dental anatomy, as it affects the tooth's fit and occlusion. The average mesiodistal diameter of the permanent maxillary canine is approximately 9.5 mm.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the mesiodistal diameter of the permanent maxillary canine is generally larger than the other incisors, making 7 mm an underestimation.
* **Option B:** This option is incorrect because the mesiodistal diameter of the permanent maxillary canine is not typically as small as 6 mm, which would be more characteristic of the incisors.
* **Option C:** This option is incorrect because the mesiodistal diameter of the permanent maxillary canine is generally not as large as 11 mm, which is more characteristic of the molars.

**Clinical Pearl / High-Yield Fact**
The permanent maxillary canine is often considered the "key tooth" in the human dentition due to its unique morphology and size. Its mesiodistal diameter is critical in dental anatomy, affecting the tooth's fit and occlusion.

**Correct Answer: C. 11 mm**