The mesial root of the maxillary first molar most commonly contains:

Correct answer: A. Two canals with one foramen

• A. Correct. The mesiobuccal (MB) root of the maxillary first molar most commonly contains two canals — MB1 and MB2 — that typically join before the apex and exit through a common or closely approximated foramina. The MB2 canal is often missed clinically.
• B. MB1 and MB2 with completely separate foramina are possible but less common than shared/joined exit.
• C. The mesial root (mesiobuccal root) of the maxillary first molar almost always has two canals, not one.
• D. Three canals in the mesial root of the maxillary first molar is extremely rare.