Which of the following statements is/are true regarding the regulation of digestive secretions?
a) pancreatic enzymes are under both neural and hormonal control

b) cholecystokinin is released by the gallbladder

c) secretin induces gallbladder contraction

d) CCK is released in response to a low pH in the duodenum

e) via the vagus nerve, acetylcholine stimulates the pancreatic acini