The correct answer is B. p53.
Squamous cell carcinoma is the second most common cancer of the skin. Mutations in the tumor suppressor p16 and p53 are commonly found in SCC’s. Normally, UV damage upregulates p53 thereby delaying cell cycle progression. DNA damage can then be repaired or the cell could undergo apoptosis. In squamous cell carcinoma, p53 exhibits loss of heterozygosity due to C to T or CC to TT mutations.
The remaining answer choices would be less likely to be found mutated in SCC.