Answer:
a)案 -> 柱 -> 責 -> 賦
案 AN - plan, proposal
柱 CHUU, hashira - pillar, column, pole
責 SEKI, se(meru) - condemn, censure, torture
賦 FU - tribute, payment, installment
b) 架 -> 棋 -> 基 -> 堤
架 KA, ka(keru), ka(karu) - hang, build (a bridge)
棋 KI - go, shogi, Japanese chess
基 KI, moto, motoi - basis, foundation
堤 TEI, tsutsumi - bank, embankment, dike