A cylinder of capacity 20 litres is filled with H₂ gas. The total average kinetic energy of translatory motion of its molecules is 1.5×10⁵ J. The pressure of hydrogen in the cylinder is
A. 2 X 10⁶ N/ m²
B. 3 X 10⁶ N/ m²
C. 4 X 10⁶ N/ m²
D. 5 X 10⁶ N/ m²