Choice A rationale:

 Radiation therapy.

Radiation therapy is not the primary treatment modality for melanoma.

While it may be used in some cases, such as adjuvant therapy after surgery, it does not primarily target melanocytes.

Choice B rationale:

 Chemotherapy.

Chemotherapy may be used for advanced melanoma, but it is not the primary treatment modality for targeting melanocytes.

Chemotherapy targets rapidly dividing cells and is generally less effective against melanoma compared to other treatments.

Choice C rationale:

 Surgical excision.

This statement is accurate.

Surgical excision is the primary treatment modality for melanoma.

It involves the removal of the melanoma and some surrounding tissue to ensure complete removal of cancerous cells.

This procedure directly targets the melanocytes within the tumor.

Choice D rationale:

 Immunotherapy.

Immunotherapy is an important treatment option for melanoma, especially in advanced cases.

However, it does not primarily target melanocytes but rather stimulates the patient's immune system to recognize and attack melanoma cells.