The Dental Hygienist Completes the Instrumentation of the Class I

The dental hygienist completes the instrumentation of the Class I furcation on the mesial of No. 14 from the lingual approach. What anatomic feature allows for this lingual access?

A) The divergence of the mesial proximal surface toward the lingual allows for this access.
B) The short mesial root trunk and the lingual location of the furcation allow for this access.
C) The proximal and furcal concavities on the mesial root allow for this access.
D) The long root trunk, close root proximity and distal orientation of the roots allow for this access.