bet dispute... plz settle

[yeotaJMU]

my roomate and i are i watching the giants game and just saw the play where a ball thrown to burress was ruled incomplete inside of 2 minutes and was replay reviewed and overturned. this incited my roomate to argue whether or not an incomplete pass can be challenged or not.

the official question is:
can a coach challenge a pass originally ruled as incomplete, whether it be on the sideline, in the endzone, or anywhere else on the field?

edit: this is a serious bet so dont be a jackass