"An emergent phenomenon of the way our biological hardware works" is one possible, entirely rational and most importantly sufficient answer. And even if we did not have an answer, that doesn't mean that there is not an entirely materialistic explanation for the phenomenon, even if we didn't find the answer yet.
Because we have hundreds of thousands of examples of previously unexplained phenomena being sufficiently and completely explained by purely naturalistic, materialistic causes.
On the other hand we have exactly zero previous examples of a phenomenon being sufficiently explained by anything supernatural.
Since we observe consciousness solely bound to the existence of, reliant on the configuration of and changeable through the change of physical properties of physical matter, we can conclude that it is an emergent property that has arisen like other properties emergent from biological matter through the well known, well defined and observable process of evolution.
Could there be an alternative explanation? Yes!
Is the god-hypothesis in any way an explanation for consciousness? No! In fact it would raise more questions. It is neither sufficient, nor rational. What it is, is a god-of-the-gaps argument, another turtle on the way down.