If $G$ is universal gravitation constant and $g$ is acceleration due to gravity, then dimensions of $\frac{G}{g}$ will be ...................

• A
  $\left[ M ^{-1} L ^2\right]$
• B
  $\left[ M ^{-1} L \right]$
• C
  $\left[ M ^{-2} L \right]$
• D
  $\left[M^{-1} L^{-2}\right]$