Final answer:
The most common areas of a welder's body that are burned by light are the neck and wrist. These areas are vulnerable to burns caused by the electromagnetic radiation from the electric arc during welding.
Step-by-step explanation:
The two most common areas of a welder's body that are burned by light are the neck and wrist, which corresponds to option a. Neck and wrist. Welder's gloves and helmet are essential protective gear that shield a welder from the electric arc. The electric arc emits high-energy electromagnetic radiation which can cause burns if skin is exposed. High intensity UVB light from the welding process can lead to skin and eye damage, including conditions like welder's flash, also known as photo keratitis or arc eye.