**Core Concept**
Actinomyces viscosus is an oral bacterium that initially colonizes the periodontal ligament (PDL) environment. It plays a significant role in the development of periodontal disease. The bacterium's ability to attach to the tooth surface is a crucial step in its colonization and subsequent infection.

**Why the Correct Answer is Right**
Actinomyces viscosus attaches to the tooth surface through a process called adsorption, where it binds to the pellicle or saliva-coated surface. The bacterium uses its surface proteins to interact with the host's proteins, such as salivary proteins, which are present on the tooth surface. This interaction allows Actinomyces viscosus to establish itself on the tooth surface, ultimately leading to the formation of a biofilm. The pellicle is a thin layer of proteins and glycoproteins that coats the tooth surface, providing a suitable environment for bacterial attachment.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the mechanism of attachment, and the term "adhesion" is too broad to be a correct answer.
**Option B:** This option is incorrect because it refers to a different type of bacterial attachment, which is not relevant to Actinomyces viscosus.

**Clinical Pearl / High-Yield Fact**
Actinomyces viscosus is a common oral bacterium that can cause periodontal disease if not properly managed. Its ability to attach to the tooth surface is a critical step in the development of periodontal disease, highlighting the importance of maintaining good oral hygiene practices.

**Correct Answer:** C.