Right answer is (a) True
To elaborate: In Co2 moulding, moulds and cores of varied sizes and shapes can be formed, this is mainly achieved by the using of binder sodium silicate that can binds the sand in any shape and size, and that is further tightened by the passing of Co2 gas. This makes the moulding process very fast and flexible, so this process is more economical, where speed and flexibility is the prime requirement.