What are 5 examples of anatomic problems that contribute to the decision on which root to remove in a root resection?

a) Radicular grooves, extra canals, thick furcation walls, accessory canals, close proximity to sinus
b) Short roots, thin furcation walls, lack of canals, distant proximity to sinus, shallow grooves
c) Accessory canals, extra roots, thin furcation walls, radicular grooves, distant proximity to sinus
d) Extra canals, thick furcation walls, accessory roots, deep grooves, close proximity to sinus