The function f(0) = θ³- 6θ² +9θ satisfies f(θ) ≥ 0 for θ≥0. During the time interval 0 ≤ t≤2π seconds, a particle moves along the polar curve r = f (0) so that at time t seconds, 0=t. On what intervals of time t is the distance between the particle and the origin increasing?
(A) 0≤1 ≤ 3 only
(B) 0≤1≤2л
(C) 1≤t≤3 only
(D) 0≤t≤1 and 3 ≤1≤ 2л only