2834. What characters can be added here so that each character contains a part of the previous character? a) 章 -> _ -> _ -> 含 b) 案 -> _ -> _ -> 肥

a) 章 -> 古 -> 吟 -> 含

章 SHOU - chapter, badge, mark

古 KO, furu(i) - old

吟 GIN - sing, chant, recite

含 GAN, fuku(mu), fuku(meru) - hold, include, contain

b)案 -> 棋 -> 期 -> 肥

案 AN - plan, proposal

棋 KI - go, shogi, Japanese chess

期 KI, GO - time, period, term

肥 HI, koe, ko(yashi), ko(yasu) - manure, fertilizer, grow fat