Retention for occlusal amalgam cavities in premolars is BEST provided by
A. Slightly undercutting of walls with inversed cone bur
B. Mesial and distal undercuts
C. Buccal and lingual undercuts
A. Slightly undercutting of walls with inversed cone bur
B. Mesial and distal undercuts
C. Buccal and lingual undercuts