— How does he get to work?

— He _____ a bike.

— How long does it _____ him to get from home to the office?

— It _____ him 20 minutes. [ ]

A. rides; takes; takes

B. rides; take; takes

C. ride; takes; takes

D. ride; take; takes

已知事件A、B仅发生一个的概率为0.3，且P(A)+P(B)=0.5，则A，B至少有一个不发生的概率为______．