Answer:
a) 炎 -> 畑 -> 累 -> 綱
炎 EN, honou - flame
畑 hatake - cultivated field
累 RUI - involvement, trouble, accumulation
綱 KOU, tsuna - rope
b) 駐 -> 素 -> 紛 -> 貧
駐 CHUU - stop, reside
素 SO, SU - element, naked, simple
紛 FUN, magi(reru), magi(rawashii) - be mistaken for, confusing
貧 HIN, BIN, mazu(shii) - poor