Differential pressure head measured by mercury oil differential manometer equivalent to

Question

Differential pressure head measured by mercury oil differential manometer (Specific gravity of oil is 0.9) equivalent to a 600 mm difference of mercury levels will nearly be                             

(a) 7.62 m of oil          (b) 76.2 m of oil

(c) 7.34 m of oil          (d) 8.47 m of oil