Question

Could the big bang have started with a black hole exploding?

Answer 1

Yes.

Explanation:

But the answer can just as easily be no. The reality is we simply do not know what existed one second prior to the big bang. Right now it is a best guess scenario. That scenario is that a singularity existed containing everything which exists in the visible universe today in such a compressed form as to possible have been the size of a grapefruit or smaller.