The correct option is D T 11 E
In the given series
The first letter of each term differs by 3 letters in backward direction.
Z, Z-3=W, W-3=T, T-3=Q,Q-3=N
The number series differs by 2 in backward direction.
15,15-2=13,13-2=11,11-2=9,9-2=7
The third letter of each term differs by 2 letters in the forward direction.
A, A+2=C,C+2=E, E+2=G
The missing term is T11E
Answer is Option C