Choose the correct order of the given alternative : 23B _ 6 _ F G _ 5D _ 8 _ H I

Explanation:-

From the alternatives, it is clear that the series can be divided in to 4 terms each - each group comprising of two numbers followed by two letters, as shown below
23 B _ / 6 _ F G/_ 5 D _ / 8 _ H I
Clearly, the first number in each group represents the position of the letter at the third place, in the English alphabet. Thus, the third missing term is the number corresponding to the position of D in English alphabet i.e., 4, which is given in (1).
Substituting other terms of (1) into the series, wer get:
23BC/67FG/45DE/ 89HI
Observe that the second number in each group represents the position of the letter at the fourth place, in the English alphabet.