[" Radius of moon is "1/4" times that of earth and mass is "1/81],[" times that of earth.The point at which gravitational field "],[" due to earth becomes equal and opposite to that of moon,is "],[" (Distance between centres of earth and moon is "60R," where "],[" R is radius of earth) "],[" (a) "5.75R" from centre of moon "],[" (b) "16R" from surface of moon "],[" (c) "53R" from centre of earth "],[" (d) "54R" from centre of earth "]