Select the combination of letters that when sequentially placed in the gaps of the given letter series will complete the series. a_ _ccde_ _ _bc_ _ _eaabc_ _ _ _aabc_ _ee

abbaacdeecdecd abeaacdecdeecd acbdecdeaacecd abcdecdeecdeaa

abeaacdecdeecd

a a b c c d e e / a a b c c d e e / a a b c c d e e / a a b c c d e e a b e a a c d e c d e e c d