Correct option is C
For M15 grade concrete, the nominal mix as per IS 456:2000 is:
Cement : Fine aggregate : Coarse aggregate=1:2:4(by volume)
Total aggregate proportion = 2+4 = 6 parts.
For 50 kg of cement, the maximum total quantity of dry aggregates (fine + coarse) is conventionally taken as about 330 kg.
This limit accounts for bulking, voids, and field batching practices used with nominal mixes.