**Core Concept**
Tumor metastasis refers to the process by which cancer cells spread from the primary site to distant organs, resulting in the formation of secondary tumors. The likelihood of metastasis depends on various factors, including the type of cancer, its aggressiveness, and the presence of specific genetic mutations.

**Why the Correct Answer is Right**
Melanoma, a type of skin cancer, has a relatively low propensity for metastasis, especially in its early stages. This is due to the presence of a unique genetic mutation that leads to the production of melanoma inhibitory activity (MIA), which inhibits the invasive and metastatic potential of melanoma cells. Additionally, melanoma cells often invade the dermal lymphatic vessels, but the lymphatic system is not as efficient in draining melanoma cells as it is for other types of cancer.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because lung cancer, particularly non-small cell lung cancer (NSCLC), is one of the most common cancers to metastasize, often to the brain, bones, and adrenal glands.
**Option B:** This option is incorrect because breast cancer, especially triple-negative breast cancer, has a high propensity for metastasis, often to the bones, lungs, and liver.
**Option C:** This option is incorrect because colorectal cancer, especially in its advanced stages, can metastasize to the liver, lungs, and peritoneum.

**Clinical Pearl / High-Yield Fact**
Melanoma is more likely to metastasize to the brain than any other type of cancer, which is why it is essential to monitor patients with melanoma for signs of central nervous system (CNS) involvement.

**Correct Answer: A. Melanoma**