A series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series
DE, GH, JK, MN, ?

Correct option is C

Observe the first letters: D (4), G (7), J (10), M (13), … The gap is +3 each time. The next letter after M(13) is P(16).
Observe the second letters: E(5), H(8), K(11), N(14), … The gap is also +3 each time. So the next letter after N(14) is Q(17).
Hence the missing term = PQ.