The mass of moon is 1 / 81 of earth's mass and its radius is 1 / 4 of that of earth. If the escape velocity from the earth's surface is 11.2 km/s, is value for the moon is

• A. 0.14 km/s
• B. 0.5 km/s
• C. 2.5 km/s
• D. 5.0 km/s