根据对话内容及方框中所给的句子补全对话，选项中有一项是多余选项。

A. Let's clean up the city parks. B. We can't put off making the plan. C. Let's put up some posters after school first. D. I'll write down all our ideas. E. I'm sure the ideas we come up with will work out well. F. We need to come up with a plan.

Tom: Clean-Up Day is coming.

Ben: We do need to make a plan, but I'm hungry. Let's have lunch first.

Tom: No. It is only two weeks from now.

Ben: You're right, Tom. So we can decide which idea is the best.

Tom: We could ask our friends to help.

Ben: Yeah. That's right. I'll ask my cousins to come.

Tom: OK. We should let more people know about it.

Ben: That's a good idea. And I can help make the posters.

Tom: Good.

Ben: I think so.

Tom: Let's begin our work now.