**Core Concept**
The crown root ratio in permanent dentition is a crucial aspect of dental anatomy, referring to the proportion of the tooth that is visible above the gum line (crown) to the portion below the gum line (root). This ratio is essential for understanding tooth structure and function.

**Why the Correct Answer is Right**
The correct answer is based on the typical anatomy of a permanent tooth, where approximately two-thirds of the tooth is comprised of the root, and one-third is the crown. This 1:2 or **2:3** ratio is a general guideline, though it can vary slightly depending on the specific tooth in question.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it suggests an equal ratio between the crown and root, which does not accurately reflect the typical anatomy of a permanent tooth.
**Option B:** This option is also incorrect as it implies a much larger crown in proportion to the root, which is not characteristic of permanent dentition.
**Option D:** Similarly, this option is incorrect because it suggests a ratio that does not align with the established anatomical proportions of permanent teeth.

**Clinical Pearl / High-Yield Fact**
Remembering that the crown to root ratio is generally **2:3** in favor of the root is crucial for dental procedures and understanding tooth stability. This ratio can affect how teeth respond to various dental treatments.

**Correct Answer:** Correct Answer: C. 2:3