Actually, I don’t agree with A, only with B.

There are enough potential terrorists; you need to fight the potential and the idea, not individuals who can easily be replaced (exceptions would be experts in explosive devices and the like).
Of course, part of the fight is deterrence—through fighting individuals.

In my opinion, while it’s true that you can’t determine whether a specific attack is connected to the release of a specific terrorist or to a specific tailwind for terrorism, it still can be determined that the two are very much related in a general sense, even if not necessarily in this specific case.
And one of the simple proofs of this is from Operation Defensive Shield, where they fought both to cut down terrorist operatives and to prove that they were fighting terrorism relentlessly, and people saw clearly that there were indeed attacks that continued even after the operation, but after some time it declined gradually until there were almost zero attacks in those years.
Which proves that although there are always attacks even without connection to the major moves against terrorism, all the major efforts against terrorism carry within them a significant reduction in the smaller individual manifestations of terrorism.