A, B, C and D are four different physical quantities having different dimensions. Now of them is dimensionless. But we know that the equation AD = C in (BD) holds true. Then which of the combination is not a meaningful quantity ?

Question

$\begin{array}{1 1}(1) A^2-B^2 - C^2 \\ (2) \frac{(A-C)}{D}\\ (3)\frac{A}{B} - C \\ (4) \frac{C}{BD} - \frac{AD^2}{C} \end{array}$