A bag consists of tokens whose labels are selected from all of the first n even natural numbers. The frequency of each label equals half the label itself. Then the variance of all the labels the bag is

A

$$\dfrac{2n^{2} + n - 2}{9}$$

B

$$\dfrac{n^{2} + 2n + 5}{9}$$

C

$$\dfrac{2\left(2n + 1\right)}{3}$$

D

$$\dfrac{2n^{2} + 2n - 4}{9}$$