I think you need to do a little bit more research before picking one of the above. Rather than pick one now, it would be better to spend a little bit of time building up some sort of a business plan (not something to show VC's but just for internal clarity).
Of the three, the 3rd option seems to make most sense to me. The things one would look for are:
1. Customer pain point. Of the three, the third is the most clear. For the other two, its not clear as to who the customer is, or even what pain point you are solving.
2. Your capability to compete (niche markets would be better). 1 and 3 seem better than 2 in this regard..
3. Cash flow/bootstrap options: 2 and 3 seem to be better, although you may end up paying for agents sitting on the bench before business builds up. 1 is the least attractive since its unclear who will pay for this initially.
4. Competition -- 1 has the least, 2 the most. However it might be better to have some competition, since (often) lack of any competition indicates lack of a market.
Of the three, the 3rd option seems to make most sense to me. The things one would look for are: 1. Customer pain point. Of the three, the third is the most clear. For the other two, its not clear as to who the customer is, or even what pain point you are solving. 2. Your capability to compete (niche markets would be better). 1 and 3 seem better than 2 in this regard.. 3. Cash flow/bootstrap options: 2 and 3 seem to be better, although you may end up paying for agents sitting on the bench before business builds up. 1 is the least attractive since its unclear who will pay for this initially. 4. Competition -- 1 has the least, 2 the most. However it might be better to have some competition, since (often) lack of any competition indicates lack of a market.
Just thoughts off the top of my head..