Step 1: Evaluate each organ–function pair.
(A) Incorrect — Protein digestion occurs in the stomach and small intestine, not large intestine.
(B) Correct — Salivary amylase in the mouth digests starch.
(C) Incorrect — Bile is produced by the liver, not the pancreas.
(D) Incorrect — Fat digestion starts in the small intestine, but the phrase "fat digestion" alone is incomplete without mentioning bile/emulsification.
Step 2: Conclusion.
Only the oral cavity correctly matches starch digestion.