Which of the following statements is not correct?
a) ALFA receptors increase arterial resistence, whereas beta2 receptor promote smooth muscle relaxation
b) The skin and splanchic vessels have predominantly alfa receptors
c) Vessels in a skeletal muscle may constrict or dilate depending on whether alfa or beta2 receptors are activated
d) Skeletal muscle vessels have predominantly alfa receptors and constrict in the presence of epinephrine and norepinephrine