下列各句中加点成语的使用，使用正确的一项是（ ）

If you go by train,you can have quite a comfortable journey,but make sure you get _fast one.

Mary felt quite ______ from theoutside world, because she couldn’t get access to the Internet and couldn’treceive any e-mail.

It is polite ______ you to give seats to theelderly.

I don’t like _____of thesweaters. Please show me a third one.