What is the correct way to say this?<br/><br/>We would be delighted if you would be able to attend.<br/>We would be delighted if you were able to attend.<br/>We would be delighted if you could attend.<br/><br/>It is for an email in quite a formal register so I thought it would be best to use the 2nd but I'm not sure if it is correct.<br/><br/>Thanks for any help