The problem is that tens (or probably hundreds) of thousands of gas stoves and oil burners still exist and are used daily, this also doesn’t cover restaurants or commercial businesses, so the impact is pretty minimal.
Your “B” suggestion is hilarious because if they wanted to they could have done it already, there are (at least) two nuclear reactors in NY State IIRC, but they have been constantly blocked at every turn from building new ones for the past few decades by the oil and gas industry. Hydroelectric plants are already in use, along with wind turbines. If it was as simple as “build renewable power plants” don’t you think we would have done that everywhere by now (where it’s feasible, obviously)?