The tube of an inclined tube manometer has its upper end open to air and the lower end connected to vertical cylinder trough having a diameter 4 times that of the tube. The slope of the tube is 1 in 4 and specific gravity of manometer liquid is 0.72. The space above the liquid in the trough is connected to a gas chamber. When the movement of meniscus in the tube is 8 cm, change in gas pressure, in height of water column, is
(A) 1.35 cm (B) 1.44 cm
(C) 1.80 cm (D) 1.53 cm