There are four types of sensory receptors that respond to one of the four primary stimuli.
Thermoreceptors detect temperature changes in the environment.
Mechanoreceptors detect changes in pressure
Photoreceptors detect the photons composing light
Chemoreceptors detect chemical stimuli and are found inside the body (for example blood vessels). They are also responsible for our sense of taste and smell.
Thus, the correct answer to the question is D. on the tongue and in the nose, to detect taste or odor.
