[dvmmh]

How is "a)" relevant at all? A proper NDA is NOT A NONCOMPETE. It just says that you can't blab what you see during the hiring process.

[laurencer]

IANAL, this varies per jurisdiction - but an NDA can prevent you from working (at least from where I am from) if there is a real risk that the information may be misused.

However, it may not even be a legal barrier, there are some companies who won't hire or engage conflicted individuals due to risk of litigation.

Definitely consult a lawyer in the appropriate jurisdiction though.