d
Dimension of \(\mathrm{A}\) is equals to dimension of \(\frac{U\left(x+B\right)}{\sqrt{x}}\) or \(\left[M L^{2} T^{-2}\right] \cdot \frac{L}{L^{\frac{1}{2}}}\) i.e \(\left[M L^{\frac{5}{2}} T^{-2}\right]\)

And dimension of \(\mathrm{B}\) is equals square of \(x\) that is \(\left[L\right]\) (because two quantities can be added only when their dimension is the same)

So dimension of \(A . B\) will be \(\left[M L^{\frac{7}{2}} T^{-2}\right]\)