If (125)x = 3125, then the value of x is?

Answer: Option C

$$\begin{array}{rl}& {\left(125\right)}^x=3125\\ & \Rightarrow {\left(5^3\right)}^x={\left(5\right)}^5\\ & \Rightarrow {\left(5\right)}^{3x}={\left(5\right)}^5\\ & \Rightarrow 3x=5\\ & \Rightarrow x=\frac{5}{3}\end{array}$$