A concave spherical mirror is cut into two halves by a plane containing its principal axis, and the halves are not displaced. Which statements are correct?

Select all that apply

• Option A

  Each half has the same focal length as the original mirror.

• Option B

  Each half can form the complete image.

• Option C

  Using only one half reduces image brightness.

• Option D

  Image size becomes half when one half is used.