You Need an Expression for the Acceleration of the Moon

Multiple Choice

You need an expression for the acceleration of the moon toward Earth.If the mass of the earth is M_e,the mass of the moon M_m,the separation of Earth and moon r,and the appropriate gravitational constant is G,the correct expression for the moon's acceleration is

A) GM_eM_m/r²
B) GM_eM_m²/r²
C) GM_m/r²
D) GM_e/r²
E) GM_e/r²M_m