A Convex Spherical Refracting Surface Separates a Medium with Index

Multiple Choice

A convex spherical refracting surface separates a medium with index of refraction 2 from air. The image of an object outside the surface is real:

A) always
B) never
C) only if it is close to the surface
D) only if it is far from the surface
E) only if the radius of curvature is small