Personally, I choose C: torture 3^^^3 people for 3^^^3 years. Why? Because I can.

Ahem. My morality is based on maximizing average welfare, while also avoiding extreme individual suffering, rather than cumulative welfare.

So torturing one man for fifty years is not preferable to annoying any number of people.

This is different when the many are also suffering extremely, though - then it may be worthwhile to torture one even more to save the rest.