All the staff in our company are considering _____ to the city centre for the fashion show. [ ]

A. to go

B. going

C. to have gone

D. having gone

在炎热夏季的（），空气中的臭氧含量最高，阳光中的紫外线辐射也最强烈，因此应避免在室外进行体育锻炼。