Concept:Each letter is shifted forward or backward according to the given rules, then the combined letters are arranged alphabetically and reduced by removing repeated letters.
Explanation:In
EARTHBOUND, the letters left of
B are
E,A,R,T,H.
They become
F,B,S,U,I by the immediate succeeding letter rule.
B remains unchanged, so it stays as
B.
The letters right of
H are
O,U,N,D, which become
N,T,M,C by the immediate preceding letter rule.
So
EARTHBOUND becomes
F,B,S,U,I,B,N,T,M,C.
In
FACTORIES, the letters before
N in the alphabet are
F,A,C,I,E.
They become
G,B,D,J,F.
The remaining letters
T,O,R,S become
S,N,Q,R.
So
FACTORIES becomes
G,B,D,S,N,Q,J,F,R.
Combining both results gives
F,B,S,U,I,B,N,T,M,C,G,B,D,S,N,Q,J,F,R.
Arranging them alphabetically gives
B,B,B,C,D,F,F,G,I,J,M,N,N,Q,R,S,S,T,U.
Dropping all repeated letters gives
C,D,G,I,J,M,Q,R,T,U.
From the right end, the order is
U,T,R,Q.
So the fourth letter from the right end is
Q.
Answer:The fourth letter from the right end is
Q, which is option C.