请根据对话内容，从方框内所给的选项中选出能填入空白处的最佳选项。选项中有一项为多余项。

A: Excuse me,  I want to go there with my son.

B: Certainly. Just go along the street and you will see the Clock Tower. The zoo is behind it.

A: 

B: No, it isn't.

A: We want to go there on foot.

B: It will take you about half an hour, but it's a hot day. You can take a bus.

A: You're right

B: You can take the No. 8 bus.

A:

B: You are welcome.