函数y=ax²+bx+c，(a≠0)在[0，+∞)上单调增的充分必要条件是( )．

A．(A) a＜0且b≥0

B．(B) a＜0且b≤0

C．(C) a＞0且b≥0

D．(D) a＞0且b≤0

Attention! _________ in the form right now, making sure that every detail supplied is accurate.

A．Filling

B．Fill

C．To fill

D．Being filled