Answer:
a) 晩 -> 勉 -> 加 -> 鳴
晩 BAN - evening, night
勉 BEN - effort, hard work
加 KA, kuwa(eru), kuwa(waru) - add, append, join, take part
鳴 MEI, na(ku), na(ru)(rasu) - cry, sing, howl, ring
b) 早 -> 古 -> 員 -> 贈
早 SOU, SA, haya(i) , haya(meru) - early, fast, hasten
古 KO, furu(i) - old
員 IN - member
贈 ZOU, SOU, oku(ru) - give, present, bestow