Answer:
c. increased vasomotor tone (tightening) of the capillaries in the area.
Step-by-step explanation:
Such type of conditions in which redness takes place on the surface of the skin or in the mucous membrane is called erythema. There are many factors that cause erythema such as injury, inflammations and some others. Histamine plays an important role in the inflammatory process that leads to redness and some other conditions. During erythema and swelling tightening of the capillaries does not takes place.