I'd be happier with the way you put it than the quote in the OP. That was more specific, spontaneous generation to evolution or god.
There's also the question of if the quote was supposed to be about any life, or life on Earth. If it is specific to Earth, then certainly alien intervention would be another possibility outside of god.
I didn't particularly like the OP either, but it is essentially correct. Even if we accept alien intervention as the reason life arose on Earth it still had to start somewhere and somehow.
Like I said, it was the specifics of the OP that bothered me, not so much when you broadened it to spontaneously or through intervention.
Just for the sake of argument (because I enjoy arguing!) a third option might be that life has always existed, but as it rises and falls it is spread throughout the universe (through comets, perhaps). Pretty thin, I realize, I was just trying to see if I could come up with another option

Since the argument that an intelligence created life leads to the question of where the intelligence came from, this came to mind.
I pretty much agree with the possibilities you present. I just like to keep that tiny sliver of doubt in mind, that perhaps my ignorance of the universe, the things which make it up, the forces which move it, how it sprang into being, etc. prevent me from seeing a third option. Practically (if anything about a discussion of this nature can really be thought of as practical) spontaneously or driven by some intelligence are the only two options.
/incoherent ramble off