Correct Answer & Explanation
Option A
The pattern is +1 for the first letter, -1 for the second, +1 for the third, and -1 for the fourth, and so on.
C (+1) = D
U (-1) = T
B (+1) = C
E (-1) = D
Following this pattern for 'SPHERE':
S (+1) = T
P (-1) = O
H (+1) = I
E (-1) = D
R (+1) = S
E (-1) = D
Therefore, 'SPHERE' is coded as 'TOIDSD'.