**Core Concept**
The question is testing knowledge of dental development, specifically the number of teeth present at a certain age. At the age of 11, children typically have a mix of primary and permanent teeth.

**Why the Correct Answer is Right**
By the age of 11, most children have started to lose their primary teeth, which are gradually replaced by permanent teeth. The first permanent molars usually erupt around the age of 6, and the central incisors start to replace primary teeth around the age of 6-7.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it underestimates the number of teeth.
**Option B:** This option overestimates the number of teeth, as not all primary teeth have been replaced.
**Option D:** This option is also incorrect as it does not account for the replacement of primary teeth.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the total number of teeth in the mouth at any given time can vary due to the ongoing process of tooth eruption and shedding.

**Correct Answer:** C. 28