Your first option comes with the major caveat that each interceptor you fire comes from a limited stockpile whose replacement rate[0] today isn't sufficient for even going 1:1, let alone accepting that multiple interceptors are required.

I'd say the real options in the near term when faced with an inbound missile is a) deciding to deplete your stockpile of interceptors with an incredibly limited replenishment rate; or b) risking a hit to a lower-value target.

Could the US go to a war economy footing and scale production? _Maybe_? I'm not entirely convinced the US can stomach the costs.

[0]: again, numbers are hard to find, but https://www.lockheedmartin.com/en-us/news/features/2026/Lock... gives a flavor of just what defenders are up against.