A double convex lens has a focal length of $25\text{cm}$. The radius of curvature of one of the surfaces is double of the other. What would be the radii if the refractive index of the material of the lens is $1.5$?

1. A
   $100\text{cm},50\text{cm}$
2. B
   $25\text{cm},50\text{cm}$
3. C
   $18.75\text{cm},37.5\text{cm}$
4. D
   $50\text{cm},100\text{cm}$