What is the primary action of chloride channel activators, such as lubiprostone, in the treatment of irritable bowel syndrome?
a) They inhibit serotonin reuptake in the gut.
b) They increase cyclic GMP production in the liver.
c) They activate type 2 chloride channels in the small intestine.
d) They block histamine receptors in the digestive tract.
e) They reduce intestinal motility.