Identify the odd one from the following.

The pattern behind the four-letter strings is checked by looking at the alphabetical order of the letters.

Option A: LKJI  →  $$L\,\rightarrow\,K\,\rightarrow\,J\,\rightarrow\,I$$
All letters move one step backward in the alphabet, so this is a sequence of four consecutive letters in reverse order.

Option B: ZYXW  →  $$Z\,\rightarrow\,Y\,\rightarrow\,X\,\rightarrow\,W$$
Again, every letter goes one step backward; a reverse consecutive sequence.

Option C: DCBA  →  $$D\,\rightarrow\,C\,\rightarrow\,B\,\rightarrow\,A$$
Here too, each letter is exactly one place earlier in the alphabet than the previous one.

Option D: QRSP  →  $$Q\,\rightarrow\,R\,\rightarrow\,S$$ (increasing order) followed by $$P$$ (a backward jump)
This breaks the pattern: the letters are not all consecutive in the same (forward or reverse) direction.

Thus the first three options are uniform reverse alphabetical sequences of four consecutive letters, whereas Option D is not. Hence, the odd one out is:

Option D which is: QRSP