Why Are Most Large Telescopes Reflectors, Not Refractors

Multiple Choice

Why are most large telescopes reflectors, not refractors?

A) Large lenses deform under their own weight, but mirrors can be supported.
B) Large mirrors need only one optical surface, achromats four surfaces to grind.
C) Reflectors do not suffer from chromatic aberration like refractors do.
D) Large, very clear lenses are harder to cast than more tolerant mirror blanks.
E) All of the above are correct.