Question

______ are receptors that can respond to painful stimuli.
mechanoreceptors
nociceptors
photoreceptors
chemoreceptors

Explanation:

Mechanoreceptors respond to mechanical stimuli (like pressure, touch). Photoreceptors respond to light. Chemoreceptors respond to chemical stimuli. Nociceptors are specialized to detect painful (noxious) stimuli, so they match the description.

Answer:

B. Nociceptors