A particle moves along the x-axis so that, at time t ≥ 0, the acceleration of the particle is a(t)=15√t. The position of the particle is 10 when t = 0, and the position of the particle is 20 when t = 1. What is the velocity of the particle at time t = 0?
(A) 10
(B) 6
(C) 0
(D) -14
