How to answer the question in a job interview you ever been convicted of a felon?

Truthfully.
Either no and that's the end of it, or yes, and tell about it.
Note that the question is CONVICTED, not just arrested and not just charged and not just tried.
You can say no if you weren't convicted.

This is easy, just tell the truth, if you went to court and was found guility, if you plead guility, did a plea agreement, then it is YES. If you were just arrested, and not convicted, it is no.