Consider two solid spheres of radii $R _ { 1 } = 1 \mathrm {~m} , R _ { 2 } = 2 \mathrm {~m}$ and masses $M _ { 1 }$ and $M _ { 2 }$, respectively. The gravitational field due to sphere (1) and (2) are shown. The value of $\frac { M _ { 1 } } { M _ { 2 } }$ is:\\
(1) $\frac { 2 } { 3 }$\\
(2) $\frac { 1 } { 6 }$\\
(3) $\frac { 1 } { 2 }$\\
(4) $\frac { 1 } { 3 }$