b) tokamaks are the best current bet (stellerators may be coming up from behind but at the present tokamaks are where the clever money is);
Disagree. Tokamaks - especially ITER is where the dumb money goes to die. I.M.O. Tokamaks are a technological rat trap. They will always be an infinitesimal amount away from "break even", performing juust well enough to suck in money but never actually delivering. Back in the day, ITER was "the biz", the Germans disagreed and built Wendelstein (which I and many others believed would never work) and now Wendelstein has gone and lapped ITER.
To really move forward it is often necessary to take a step back in finances, performance, whatever - we see this in computing, the top-of-the-range, best performance per dollar kit, is ruined by the worse (on all parameters), yet more adaptable technologies that can be evolved.
d) Controlled fusion is really hard to do. Pouring money on it does not really change this (much) unless one goes "Full-On Apollo" on the problem - Which I do think that we should, actually, both for our own and for the planets sake. Every dollar spent on oil is a direct donation to terrorism and the destruction of the ecosystem.
An Apollo-style program, several alternative paths - because this is hard and therefore will take real time and effort - is what we should do.
We can still use ITER, but ITER should be just one of many bets made.