Select the combination of letters that when sequentially placed in the blanks of the given series, will logically complete the series.
_JDIF_EJGL_KHMG_INH_

Given: _JDIF_EJGL_KHMG_INH_

Let's check all the options:

Option (a): CKELO

Sequence: C J D I F K E J G L E K H M G L I N H O   (Not Follow Logical Pattern)​
​Option (b): CIEKO

Sequence: C J D I F I E J G L E K H M G K I N H O    (Not Follow Logical Pattern)​
​Option (c): EKFLM

Sequence: E J D I F /K E J G L /F K H M G /L I N H M   (Follow Logical Pattern)

Logic: Pattern are +5, -6, +5, -3 alternatively in English alphabet.

E + 5 = J; J - 6 = D; D + 5 = I; I - 3 = F; F + 5 = K; K - 6 = E; E + 5 = J; J - 3 = G; G + 5 = L; L - 6 = F
F + 5 = K; K - 3 = H; H + 5 = M; M - 6 = G; G + 5 = L; L - 3 = I; I + 5 = N; N - 6 = H; H + 5 = M

​Option (d): EIFKM

Sequence: E J D I F I E J G L F K H M G K I N H M    (Not Follow Logical Pattern)

Thus, the correct option is (c) EKFLM