Question

what can a person do to limit exposure to x - rays?
wear sunblock
avoid cigarette smoke
wear a protective lead vest
avoid chemicals

Explanation:

X - rays are a form of ionizing radiation. Lead is effective at blocking ionizing radiation. Wearing a protective lead vest can limit exposure to X - rays. Sunblock protects against UV rays, avoiding cigarette smoke reduces exposure to harmful chemicals in smoke, and avoiding chemicals has no direct relation to X - ray exposure.

Answer:

wear a protective lead vest