from deduction rules (http://aptitude.gateoverflow.in/2346/cat1999-125#a2370)
option A ) 1. MD is an actor
2.Some actors are pretty
given conclusion : MD is pretty. , here no conclusion as middle term(actor) is not distributed , it violate rule 2 ) so its false
option B )1.Some men are cops
2.All cops are brave
given conclusion : Some brave people are cops., its false bcoz it contain middle term cops , which is voilate rule 2)
option C) 1.All cops are brave.
2.Some men are cops.
given conclusion : Some men are brave. which is correct , follow all rules
option D ) 1. All actors are pretty
2. MD is not an actor
given conclusion : MD is not pretty. , its false , bcoz pretty is distributed in given conclusion (2.4), but in premise 1 its not distributed so it must be non distributed in conclusion also , hence violate rule 7 .
hence C is correct so option 2) is correct ans