2000. What characters can be added here so that each character contains a part of the previous character? a) 妄 -> _ -> _ -> 含 b) 案 -> _ -> _ -> 幸

a) 妄 -> 如 -> 吟 -> 含  

妄  MOU, BOU - without reason, without authority

如  JO, NYO - equal, like, as, as if

吟  GIN - sing, chant, recite

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

b) 案 -> 棋 -> 基 -> 幸  

案  AN - plan, proposal

棋  KI - go, shogi, Japanese chess

基  KI, moto, motoi - basis, foundation

幸  KOU, shiawa(se), sachi - happiness, good fortune