Consider two boxes containing ideal gases A and B such that their temperatures, pressures and number densities are same. The molecular size of A is half of that of B and mass of molecule A is four times that of B. If the collision frequency in gas B is $$32 \times 10^{18}/s$$ then collision frequency in gas A is _____________/s.

A

$$32 \times 10^{8}$$

B

$$2 \times 10^{8}$$

C

$$8 \times 10^{8}$$

D

$$4 \times 10^{8}$$