In the microbiology lab, nutrient agar is used to?

a) culture viral cells
b) identify bacteria in a patients sample
c) isolate pure bacterial colonies from patient sample
d) determine if the bacteria in a patients sample has a capsule

I know it is either B or C, but was wondering which one out of the 2 is correct. B is more general whereas C is more specific and it is confusing me. Any help is appreciated