In triangle ABCABCABC, if sinA:sinB:sinC=2:3:4\sin A : \sin B : \sin C = 2 : 3 : 4sinA:sinB:sinC=2:3:4, find cosC\cos CcosC.
−14-\frac{1}{4}−41
−38-\frac{3}{8}−83
−12-\frac{1}{2}−21
14\frac{1}{4}41