Final answer:
Earplugs are the safety equipment designed to prevent sparks and spatter from entering the ear canal during welding.
Step-by-step explanation:
The object that stops sparks and spatter from entering and burning the ear canal during welding operations is b) Earplugs.
While a welding helmet is essential for face and eye protection, it does not protect the ears. Safety glasses protect the eyes, and a hard hat protects the head, but only earplugs are designed to fit inside the ears to protect the ear canal from foreign particles such as sparks and spatter that can result from welding.