B

Indirect retainers counteract rotation of a distal-extension RPD around its fulcrum line; the farther they are from that line, the longer the lever arm and the greater the resistance to lifting forces. Consequently, they are deliberately positioned on teeth located as far away from (anterior to) the fulcrum line to maximize leverage [Saito, 1989, PMID 2489568; McDowell & Fisher, 1982, PMID 7040637].