A Concave Refracting Surface of a Medium with Index of Refraction

Multiple Choice

A concave refracting surface of a medium with index of refraction n produces a real image no matter where an object is placed outside:

A) always
B) only if the index of refraction of the surrounding medium is less than n
C) only if the index of refraction of the surrounding medium is greater than n
D) never
E) none of the above