If sinθ = 4cosθ, then what is the value of sinθcosθ?

Answer: Option C

$$\begin{array}{rl}& \sin \theta =4\cos \theta \\ & \tan \theta =4\\ & \sin \theta .\cos \theta =\frac{4}{\sqrt{17}}\times \frac{1}{\sqrt{17}}=\frac{4}{17}\end{array}$$