Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.A C _ E _ A _ D E F _ C D _ F

Let's find the repeating structural pattern of the given series by analyzing the total number of letter positions (15 letters):Let's divide into groups of 5 letters:A C _ E _ | A _ D E F | _ C D _ FBy comparing corresponding positions of the groups:Position 1: A, A, _ $\to$ must be APosition 2: C, _, C $\to$ must be CPosition 3: _, D, D $\to$ must be DPosition 4: E, E, _ $\to$ must be EPosition 5: _, F, F $\to$ must be FThus, the recurring base pattern is A C D E F.Let's list the missing characters required to fill the blanks across the series:1st blank: D2nd blank: F3rd blank: C4th blank: A5th blank: EThe sequence of letters is D, F, C, A, E, which matches Option B.