Same gas is filled in two vessels of the same volume at the same temperature. If the ratio of the number of molecules is $1: 4$, then

A. The r.m.s. velocity of gas molecules in two vessels will be the same.

B. The ratio of pressure in these vessels will be $1: 4$.

C. The ratio of pressure will be $1: 1$.

D. The r.m.s. velocity of gas molecules in two vessels will be in the ratio of $1: 4$.

Choose the correct answer from the options given below :