If in the word "BALLOON", all the consonants are changed to the 3rd preceding letter and all the vowels are changed to the immediately preceding letter as per the English alphabetical series from left to right, and all the letters are then arranged as per the English alphabetical series from right to left, then the position of how many letters remains unchanged?

B A L L O O N Consonants: B, L, L, N Vowels: A, O, O Applying the rule: B -> Y (3 preceding) L -> I (3 preceding) L -> I (3 preceding) N -> K (3 preceding) A -> Z (preceding) O -> N (preceding) O -> N (preceding) Result: Y Z I I N N K Reverse alphabetical order: Z Y N N K I I The original order is B A L L O O N. Comparing positions: B is in position 1, Z in position 1. No change. In the original order, A is in 2nd position. In the transformed order, Y is in 2nd position and so on. Therefore, none of the letter maintains its position.