Which of the following groups of letters when sequentially placed from left to right will complete the given series?
cd_fc_efcdefcde_cdefcde_cdef

Correct option is C

Given:
cd_fc_efcdefcde_cdefcde_cdef
Option (a) efdf
cd ef/c fefcdefcde dcdefcde fcdef (Sequence is not followed.)
Option (b) cddf
cd cf/c defcdefcde dcdefcde fcdef (Sequence is not followed.)
Option (c) edff
cd ef/c def/cdef/cde f/cdef/cde f/cdef (Sequence followed.)
Option (d) fcde
cd ffc c/efcdefcde dcdefcde ecdef (Sequence is not followed.)
Correct answer is (c) edff