From the following combinations of physical constants (expressed through their usual symbols) the only combination , that would have the same value in different systems of units , is :

Question

$(a)\;\large\frac{ch}{2 \pi \in_{0}^{2}}\qquad(b)\;\large\frac{e^{2}}{2 \pi \in_{0}Gm_{e}^{2}} \qquad(c)\;\large\frac{\mu_{0} \in_{0}}{c^{2}}\large\frac{G}{h e^{2}}\qquad(d)\;\large\frac{2 \pi \sqrt{\mu_{0}\in_{0}}}{ce^{2} }\large\frac{h}{G}$