I have no idea what I would have ideally liked, but in reality I made a comment one night about the future of our relationship, something like where was it heading (and this was after years of being together). We kinda of informally agreed to get married then. Over the next 6months, we would mention it very now and again but nothing was ever really made about. Except for, if he did want to buy any jewellery for me what colours would I prefer.. At the 6 months mark, dh proposed, out of the blue, in our empty house that we were moving out of, me needing to pee (yep he kept a pregnant woman waiting to pee, so not a good idea ). He designed the ring entirely, even to sifting through the stones to find the perfect ones to use.
But I like surprises, so maybe b or d.