Answer:
a) 架 -> 柱 -> 責 -> 販
架 KA, ka(keru), ka(karu) - hang, build (a bridge)
柱 CHUU, hashira - pillar, column, pole
責 SEKI, se(meru) - condemn, censure, torture
販 HAN - sell
b) 案 -> 柱 -> 青 -> 胴
案 AN - plan, proposal
柱 CHUU, hashira - pillar, column, pole
青 SEI, SHOU, ao(i) - blue
胴 DOU - torso, trunk