Concept:Differentiate an exponential function with a variable exponent by rewriting it as a power of x.Explanation:Let y=5logx.Using the identity alog10b=blog10a, we get y=xlog5.Differentiate using the power rule dxd(xn)=nxn−1.Here n=log5.So, dxdy=(log5)⋅xlog5−1.This matches option C.Answer:dxdy=log5⋅xlog5−1.