Consider two physical quantities A and B related to each other as $E=\frac{B-x^2}{A t}$ where $E, x$ and $t$ have dimensions of energy, length and time respectively. The dimension of $A B$ is

• A

  $\mathrm{L}^{-2} \mathrm{M}^1 \mathrm{~T}^0$

• B

  $\mathrm{L}^2 \mathrm{M}^{-1} \mathrm{~T}^1$

• C

  $\mathrm{L}^{-2} \mathrm{M}^{-1} \mathrm{~T}^1$

• D

  $\mathrm{L}^0 \mathrm{M}^{-1} \mathrm{~T}^1$