**Core Concept**
The etiology of dental caries involves the interaction of bacteria with the host's oral environment, leading to the demineralization of tooth enamel. This process is primarily mediated by acid production from the fermentation of dietary carbohydrates by oral bacteria.

**Why the Correct Answer is Right**
For a bacterium to be considered a serious contributor to dental caries, it must adhere to the tooth surface and produce acid through glycolysis of fermentable carbohydrates. This acid production leads to the demineralization of tooth enamel, causing the characteristic lesions of dental caries. The primary acid-producing bacteria in the oral cavity are those that possess the enzyme glucosyltransferase, which enables them to produce extracellular polysaccharides and adhere to the tooth surface.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the requirement for acid production, which is a critical factor in the etiology of dental caries.
**Option B:** This option is incorrect as it does not mention the importance of adherence to the tooth surface, which is necessary for the bacterium to exert its pathogenic effects.
**Option C:** This option is incorrect as it does not specify the role of glucosyltransferase in acid production and adherence to the tooth surface.

**Clinical Pearl / High-Yield Fact**
To remember the key bacteria involved in dental caries, recall the acronym "S. mutans" (Streptococcus mutans), which is a major acid-producing bacterium that adheres to the tooth surface and is a significant contributor to the etiology of dental caries.

**Correct Answer: C.**