A. The size of the centripetal force Fn=mv2R. Therefore A is wrong.
B. According to Newton’s second law, N-mg=mv2R, then N=mg+mv2R. So the sliding friction force f=μN=μ(mg+mv2R). Therefore, B is wrong and C is correct.
D. Since the direction of the resultant force of the gravity support force is vertically upward and the direction of the sliding friction force is horizontally to the left, the direction of the resultant force of the object is obliquely upward to the left. Therefore D is correct.
So choose CD.