**Core Concept**
Dermatophytes are a type of fungus that infect keratin-containing tissues, such as skin, hair, and nails. These fungi are responsible for a range of diseases, including tinea infections. The infection occurs when the fungus penetrates the keratin layer and begins to break down the protein.

**Why the Correct Answer is Right**
The mechanism of dermatophyte infection involves the production of keratinases, which are enzymes that break down keratin proteins. The fungus then uses this broken-down keratin as a source of nutrients. Dermatophytes infect keratin-containing tissues because they have a unique ability to produce keratinases, allowing them to degrade keratin and obtain the necessary nutrients for growth.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because dermatophytes do not typically infect mucous membranes, which are rich in mucin and do not contain keratin.
**Option B:** This option is incorrect because dermatophytes do not typically infect internal organs, which are rich in collagen and elastin, but not keratin.
**Option C:** This option is incorrect because dermatophytes do not typically infect bone, which is a calcified tissue and does not contain keratin.

**Clinical Pearl / High-Yield Fact**
A key clinical correlation is that dermatophytes are more likely to infect areas of the body that are subjected to friction or trauma, such as the feet and hands. This is because the damage to the keratin layer allows the fungus to penetrate more easily.

**Correct Answer: C.