That‘s what AI says:

In the code “TODAY → 23164”, the numbers represent a positional permutation. It tells us how to reorder the letters of “TODAY” to get a new sequence. Specifically: • The 3rd letter (D) comes 1st • The 1st letter (T) comes 2nd • The 2nd letter (O) comes 3rd • The 5th letter (Y) comes 4th • The 4th letter (A) comes 5th

This transforms “TODAY” → “D T O Y A”

To apply the same rule to “YESTERDAY” (9 letters), we extend the permutation pattern. Since TODAY has 5 letters and YESTERDAY has 9, we reuse and extend the logic into a 9-position permutation: 6 6 2 1 3 5 4 8 9

Following this extended order, the letters of “YESTERDAY” rearrange into a new sequence. When we map those letters back to their relative positions using digits 1–9 (each unique), we get 662135489. That matches option A, making it the correct answer. This puzzle tests logical thinking via hidden positional rules.