When May the Defence of Non Est Factum Be Raised

When may the defence of non est factum be raised?

A) when a person signs a document but his attention has not been drawn to a particularly onerous term
B) when there is a radical difference between what a person signed and what the person thought he was signing,and the signatory was not careless in signing or in not reading the documents
C) when a person signs a document but fails to read it first
D) when the defendant forgot to have the plaintiff sign the contract
E) when there is no written evidence of the contract