Choose the correct order of the given alternative : D _ 6EGP _ HJ _ 12KMB15 _

From the alternatives, it is clear that the series can be divided in to 4 groups of four terms each - each group comprising of three letters and a number at the third place.
D _ 6E/GP _ H/J _ 12K/MB15 _
Studying the pairs 6E and 12K, we find in each group the number is one more than the number represents the position of the letter at the forth place, in the English alphabet.
Thus, putting A = 1, B = 2, ......y = 25, Z = 26,
We have,
2nd missing tertm = H + 1 = 8 + 1 = 9;
4th missing term = 15 - 1= 14th letter = N
Thus , the 2nd and 4th missing terms are 9 and N respectively, which are given only in (4).