If the sum of first n even natural number is equal to k times the sum of first n odd natural numbers, then k =

Answer: Option D

Sum of n even natural number = n(n+1)
and sum of n odd natural numbers = n²
$$\begin{array}{rl}& \therefore n\left(n+1\right)=k{n}^2\\ & \Rightarrow k=\frac{n(n+1)}{n^2}\\ & =\frac{n+1}{n}\end{array}$$