The correct option is D fperra
The given words and their codes are as follows:
(1) NATION - agvnab
(2) REMOTE - rzgrbi
(3) STAIR - efgnv
(4) FORMAL - bensyz
(5) COMMON - zabzpb
(6) FOR - ebs
In the first word, the letter N is repeated and so is the code a. Hence, for N, the code is a. Similarly, from the second word, the code for E is 'r'. In first and sixth words the letter o is common and so is the code b. Hence, the code for o is b. In the fifth word, the letter m is repeated and so is the code z. Hence, the code for m is z. Similarly, the codes for the remaining letters can be determined.
The letters and their respective codes are as follows:
Letter: A C E F I L M N O R S T
Code letter: n p R s v y z a b e f G
The code of 'SCREEN' is fperra.