[問題]聽力突破 短對話技巧 中but類型題 練習 Q34

[molecular]

Man: See that guy over there in the corner? He comes in every Thurseday night around six and he sits there, for hours.
Woman: It's odd, but there is not much we can do as long as he orders something that is.
What does the woman imply?
Answer: (B) The customer hasn't done anything wrong.

請問這裡的that is 是作什麼用法?? 在這句話裡的角色地位是?

[molecular]

這題真的無解了嗎??