Answer:

(4) WQHC

Step-by-step explanation:

Positions in English alphabet:

FIGHTERS - 6,9,7,8,20,5,18,19

TQUTFUJI - 20,17,21,20,6,21,10,9

The following pattern is observed when the positions of every respective letter of the above words are added:

26,26,28,28,26,26,28,28

Which implies the word CITY and its complement must also follow the pattern i.e series of sum of positions = 26,26,28,28

CITY - 3,9,20,25

Required positions - 26-3, 26-9, 28-20, 28-25

= 23,17,8,3

Hence, required word = WQHC