Name a common vasoconstrictor used in dental anesthesia.

Epinephrine is commonly used in dental anesthesia as a vasoconstrictor. Its primary role in this context is to constrict blood vessels, which reduces blood flow to the area where the anesthetic is administered. This not only helps to prolong the effect of the anesthetic by keeping it localized, but also decreases bleeding in the surgical area, leading to a clearer field for the dentist.

Epinephrine works by stimulating alpha-adrenergic receptors, which induces vasoconstriction, and it also activates beta-adrenergic receptors to some extent, which can influence heart rate and respiratory function. This dual action maximizes the efficacy of the anesthesia while managing hemostasis.

While norepinephrine, dopamine, and adrenaline might be associated with similar physiological effects, epinephrine is the specific vasoconstrictor widely recognized and utilized within dental practices for anesthesia. Additionally, adrenaline is actually another name for epinephrine, so choosing "C" is particularly relevant in highlighting the significance of epinephrine in dental settings.