For each natural number k. Let `C_(k)` denotes the circle with radius k centimetres and centre at origin. On the circle `C_(k)` a particle moves k centrimetres in the counter-clockwise direction . After completing its motion on `C_(k)` the particle moves to `C_(k+1)` in the radial direction . The motion of the particle continue in this manner. The particle starts at ( 1,0). If the particle crosses the positive direction of the X -axis for the first time on the circle `C_(n)`, then `n ="__________________"`.

Options

A. 4
B. 5
C. 6
D. 7

Answer

D