Let I represent the current through a conductor, R its resistance,...

The dimensional formula for potential difference $V$ is $[M L^2 T^{-3} I^{-1}]$.

The dimensional formula for resistance $R$ is $[M L^2 T^{-3} I^{-2}]$.

The dimensional formula for current $I$ is $[I]$.

Checking the dimensions of the product $IR$:

$[I][R] = [I] \times [M L^2 T^{-3} I^{-2}] = [M L^2 T^{-3} I^{-1}]$

This matches the dimensional formula for $V$.

Checking the other relations:

$[I][V] = [I] \times [M L^2 T^{-3} I^{-1}] = [M L^2 T^{-3}] \neq [R]$

$[V][R] = [M L^2 T^{-3} I^{-1}] \times [M L^2 T^{-3} I^{-2}] = [M^2 L^4 T^{-6} I^{-3}] \neq [I]$

$[I^2][R] = [I^2] \times [M L^2 T^{-3} I^{-2}] = [M L^2 T^{-3}] \neq [V]$

Thus, the correct relation according to dimensional analysis is $V = IR$.