The dimensions of potential difference are

The potential difference V between two points is the amount of work done in moving a unit charge from one point to the other.

Thus,          $V= \frac{work done}{charged moved} = \frac{W}{q}$

 $$\begin{gathered} \therefore Dimensions of V=\frac{M{L}^2{T}^{-2}}{Q}= M{L}^2{T}^{-2}{Q}^{-1} \\ = M{L}^2{T}^{-3 }{A}^{-1} (\because Q = AT) \\ Hence, the correct choice is 1 \end{gathered}$$