A particle moves along positive branch of the curve, y=x/2, where x=t³/3, x and y are measured in maters and t in second, then:

A. The velocity of particle at t=1 s is i+12j
B. The velocity of particle at t=1 s is 12i+j
C. The acceleration of particle at t=2 s is 2i+j
D. The acceleration of particle at t=2 s is i+2j