Alex works at his computer for several hours a day. He is careful to sit up straight at the computer with his feet on the floor and to keep his muscles relaxed, and stays off his computer after 6 p.m. For what kind of computer-related health problems is Alex still at risk?

Amusculoskeletal problems

Bvision problems

Csleep problems

Dheadaches

what is one way to avoid computer related health problems?
 A. always use a track pad instead of a mouse.
B. position your computer so it faces a window.
C. look closely at the screen at all times to maintain your concentration level.
D. take frequent breaks that include moving around and stretching.