**Core Concept**
Collagen is a major structural protein found in the extracellular matrix, providing strength and elasticity to tissues. In rhabdomyosarcoma, a type of soft tissue sarcoma, abnormal muscle cells may produce and accumulate collagen, leading to its distribution within the tumor cells.

**Why the Correct Answer is Right**
In rhabdomyosarcoma, the accumulation of collagen is due to the abnormal expression of collagen genes by the tumor cells. This leads to the deposition of collagen fibers within the tumor stroma, which can be seen on histological examination. The presence of collagen in rhabdomyosarcoma is a characteristic feature that helps in its diagnosis and differentiation from other types of soft tissue tumors.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because collagen is not typically found in normal muscle cells. In rhabdomyosarcoma, the abnormal expression of collagen genes leads to its accumulation within the tumor cells.
**Option B:** This option is incorrect because elastin, not collagen, is the main protein responsible for the elasticity of tissues. While elastin may be present in some soft tissue tumors, it is not a characteristic feature of rhabdomyosarcoma.
**Option C:** This option is incorrect because laminin is a protein component of the basement membrane, not a type of collagen. While laminin may be present in some soft tissue tumors, it is not a characteristic feature of rhabdomyosarcoma.

**Clinical Pearl / High-Yield Fact**
Rhabdomyosarcoma is a type of soft tissue sarcoma that typically affects children and young adults. It is characterized by the presence of abnormal muscle cells that produce and accumulate collagen, leading to its distribution within the tumor cells. Recognizing the presence of collagen in rhabdomyosarcoma is crucial for its diagnosis and differentiation from other types of soft tissue tumors.

**Correct Answer: B. Muscle-specific actin is distributed in rhabdomyosarcoma cells.**