Re: Formatting has two options
A simple overwrite with zeroes will defeat all but very high-$ attempts to recover information.
I assume the NSA is not about to divulge how much they can recover from such, regardless of the answer.
If the information on the disk would/might be that valuable, then physical destruction is obviously the correct solution.
Strings on the raw disk will show content, enough to make the raw disk a real security risk.