A vessel of volume V=30 litre is separated into three equal parts by stationary semi permeable membranes. The left, middle and right parts are filled with mH=30 gm of hydrogen, mO=160 gm of oxygen and mN=70 gm of nitrogen respectively. The left partition lets through only hydrogen while the right partition lets through hydrogen and nitrogen. If the temperature in all is 300 K, the ratio of pressure in the three compartments will be
(a) 4 : 9 : 5
(b) 1.3 : 4.5 : 2
(c) 9 : 4 : 5
(d) 9 : 5 : 4