Which of the following represents the most likely location of a second MB canal when accessing a maxillary first molar?

A. The canal orifice is generally located slightly buccal to or directly on a line between the primary MB canal and distal orifices.
B. The canal orifice is generally located directly distal to the MB canal orifice.
C. The canal orifice is generally located mesial to or directly on a line between the primary MB canal and palatal orifices.
D. The canal orifice is generally located equidistant between all three canals in the central pulpal floor.