The correct answer is A. CK.

CK needs to be checked at baseline and periodically during treatment with sonidegib. Lipid levels, TSH, ALT/AST, and CBC do not need to be checked prior to onset of sonidegib.

References:

Villani A, Fabbrocini G, Costa C, Scalvenzi M. Sonidegib: Safety and Efficacy in Treatment of Advanced Basal Cell Carcinoma. Dermatol Ther (Heidelb). 2020;10(3):401-412.