(256)0.16 × (256)0.09 = ?

Answer: Option A

(256)^0.16 × (256)^0.09 = (256)^{(0.16 + 0.09)}
$$\begin{array}{rl}& ={\left(256\right)}^{0.25}\\ & ={\left(256\right)}^{\frac{25}{100}}\\ & ={\left(256\right)}^{\frac{1}{4}}\\ & ={\left(4^4\right)}^{\frac{1}{4}}\\ & =4^1\\ & =4\end{array}$$