A point particle of mass m moving with velocity u in a straight line is subjected to a constant acceleration at an instant $$t = 0$$. Sometime later, at time $$t = n$$, its velocity is found to be n time the initial velocity. The distance covered by the particle during the time interval $$t = 0$$ to $$t = n$$ is expressed as

A

$$\frac{n(n + 1)u}{2}$$

B

$$\frac{(n - 1)u}{2}$$

C

$$\frac{1}{2}nu^2$$

D

$$\frac{2u(n - 1)}{n}$$