Something like (2a) or (2c) is probably the closest thing to a consensus view of what the Republic is about. But quite a few scholar still take one of the variations of (1). Karl Popper (author of The Open Society and its Enemies) is probably the most well known outside of the world of academic philosophers.
It's easy to see why it leaves a bad taste in the mouth of many moderns. On a superficial level at least, a structure of a nation like modern Iran seems to owe much to the sort of structure advocated in Plato's political works. It would be an interesting exercise to examine whether or not the parallels are more than superficial.
"To this day that was the most bullshit caesar salad I have every experienced..." - triggerfinger