I also vote (c) - but more towards “the system sucks” side since it’s supposed to be all sorts of amazing capabilities when set to fully automatic operation.
That said, since the units were so new, there almost *had* to have been some Russian cadre training the Syrian operators on their new hardware. They would almost certainly have been assisting or operating the things in a crunch. The fact that the systems didn’t hit a single craft on the way in or out has to be really disturbing.
My rule of thumb for Russian high tech and the claims made by the Russians about same: Halve the effective range, MTBF, and the other claimed capabilities, double the amount of required maintenance claimed, and you generally have a pretty accurate picture of what they’re trying to sell you.
Alternatively, if the advance raid by the Israeli commandos got so close as to collect soil samples from the target, another raid may have been to sabotage their air defenses.