In a circular motion of a particle the tangential acceleration of the particle is given by `a_(t) = 2t m//s^(2)`. The radius of the circle described is `4m`. The particle is initially at rest. Time after which total acceleration of the particle makes `45^(@)` with radial acceleration is :
A. 1 sec
B. 2 sec
C. 3 sec
D. 4 sec
