Eonwe good points. I brought that question up because of the Eru as murderer topic. It's the whole free will issue, and how/why evil is allowed to happen. It's all so subjective and relative. Its a very human debate especially concerning the ringbearers. But, for arguments sake, let's conjecture.
If one subscribes to the idea that it's all free will, then the only other strength to the argument is chaos. It was a dumb-luck random event that Deagol saw something shiny in the river. Bilbo's hand fell on to the ring by sheer coincidence. Bilbo being on the Quest of Erebor just a happenstance, etc.
No example of free will there, right? Dont even bring up what the ring willed (lol). The insertion of magical or fantastic elements just muddies up the picture to me. In this case, IMHO, the only thing the ring brings to the story at this point is that it is an actual physical manifistation of Evil on earth. The "free" choices made at Mt Doom by Frodo and Gollum are exactly the same: we are fallen creatures all of us.
I dont read a lot of preachy overtones in the works, but I do subscribe to the idea that Gollum's life and death, as was Sauron's, Aragorn's, Galadriel's, Morgoth's etc etc were all part of Eru's plan. They all intertwine and they all had a purpose to fufill. Eru nudged Gollum, as much as he whispered in Gandalf's ear that Bilbo needed to go on the Quest.
I go for A and B
