Some Research Telescopes Have Secondary Mirrors That Block the Central

Multiple Choice

Some research telescopes have secondary mirrors that block the central part of the larger primary mirror. What problem does this introduce for observations?

A) Because the secondary mirror blocks part of the primary, there is a hole in the center of the resulting image.
B) Because the secondary mirror diverts light away from the original path, it distorts the image.
C) Because the secondary mirror blocks part of the primary, the image is darker.
D) There is no disadvantage to this arrangement.