具有σ-π超共轭效应的分子是（）

aditional dress at the fashion show yesterday evening Joe: I think it’s very graceful for Chinese girls to wear a dress like that.Bob: So do I. In fact, it looked traditional but stylish to me.Joe: Do you think people can wear that stuff and walk around the streets Bob: Yes, of course. Don’t forget it stands for our traditional culture.Joe: ___________________________________. It depends.A．I don’t think it is always proper to wear a cheongsam outsideB．I don’t think it is alright to wear a cheongsam outsideC．I don’t think it is fashion to wear a cheongsam outsideD．I don’t think we should popularize this kind of fashion style

A．how much did it costB．how much it costsC．how much it costeD．it cost how much