Decoding the Pattern: MANGO to LZMFN

The problem presents a coding puzzle where the word MANGO is transformed into LZMFN. We need to identify the underlying pattern to decode APPLE.

Let's analyze the transformation letter by letter:

• M is replaced by L (M - 1 = L)
• A is replaced by Z (A - 1 = Z, wrapping around the alphabet)
• N is replaced by M (N - 1 = M)
• G is replaced by F (G - 1 = F)
• O is replaced by N (O - 1 = N)

The consistent pattern is that each letter in the original word is shifted one position backward in the alphabet (a shift of $-1$).

Applying the Pattern to APPLE

Now, we apply the same $-1$ shift pattern to the word APPLE:

• A shifts back to Z (A - 1 = Z)
• P shifts back to O (P - 1 = O)
• P shifts back to O (P - 1 = O)
• L shifts back to K (L - 1 = K)
• E shifts back to D (E - 1 = D)

Combining these shifted letters, we get ZOOKD.

Conclusion

Therefore, following the observed coding logic, APPLE is written as ZOOKD in that language, matching Option 4.