In a certain code, COMPATIBLE is written as BQNPDDKAHS. How is STABILISED written in that code?

Answer: Option C

The letters in the first half and second half of the word are written in the reverse order and in the group of letters so obtained, each letter in the first half is moved one step forward while that in the second half is moved one step backward, to get the code.
Thus, we have :
STABILISED => STABI/LISED => IBATS/DESIL => JCBUT/CDRHK