Step 1: Concept
Secretin is a digestive hormone released by the duodenum.
Step 2: Analysis
When acidic chyme enters the small intestine, secretin is released. It stimulates the pancreas to secrete a watery pancreatic juice rich in bicarbonate ions to neutralize the acid.
Step 3: Conclusion
Secretin primarily stimulates the production of pancreatic juice.
Final Answer:(B)