Each consonant in the word TIRADES is replaced by the previous letter in the English alphabet and each vowel is replaced by the next letter in the English alphabet. The resulting new letters are then arranged in alphabetical order. Which of the following letters will be fourth from the right end in this final arrangement?

Introduction / Context:
This question combines letter substitution with alphabetical ordering. Such alphabet test questions are common in logical reasoning sections and measure the ability to apply systematic transformations. We must treat consonants and vowels differently, apply the correct substitution to each letter of the word TIRADES, and then sort the resulting letters. Finally, we identify a particular position from the right in this sorted list.

Given Data / Assumptions:
- Original word: T I R A D E S.
- Consonants are replaced by the previous letter in the alphabet.
- Vowels are replaced by the next letter in the alphabet.
- After substitution, all new letters are arranged in alphabetical order.
- We must find the letter that is fourth from the right end of this final ordered sequence.

Concept / Approach:
First, we classify each letter as vowel or consonant. Then we substitute using the given rule: consonants shift one step backward, vowels one step forward. Once we have all transformed letters, we arrange them in alphabetical order. From that sorted list, we count positions from the right hand side to find the required letter. Carefully tracking each transformation prevents errors in the final step.

Step-by-Step Solution:
Step 1: Identify vowels (A, E, I, O, U) and consonants in TIRADES: T, R, D, S are consonants; I, A, E are vowels. Step 2: Apply substitution to each letter: T (consonant) becomes S. I (vowel) becomes J. R (consonant) becomes Q. A (vowel) becomes B. D (consonant) becomes C. E (vowel) becomes F. S (consonant) becomes R. Step 3: The transformed letters are S, J, Q, B, C, F, R. Step 4: Arrange these letters alphabetically: B, C, F, J, Q, R, S. Step 5: Count from the right: S is first from the right, R is second, Q is third, J is fourth. Therefore, the required letter is J.

Verification / Alternative check:
Double check the mapping for each letter: ensure that each consonant moved one step back and each vowel one step ahead. Verify that B, C, F, J, Q, R, and S are listed in correct alphabetical order. Then recount from the right side to confirm that the sequence from right to left is S, R, Q, J, F, C, B, making J clearly fourth from the right. This cross check confirms that no letter was omitted or mis ordered.

Why Other Options Are Wrong:
- "S" is the first letter from the right, not the fourth.
- "Q" is the third from the right in the final arrangement.
- "U" does not appear anywhere in the transformed set of letters, so it cannot be correct.
Only "J" corresponds to the specified fourth position from the right.

Common Pitfalls:
Students may mistakenly treat all letters with one rule or forget to distinguish vowels from consonants. Others may apply the shift in the wrong direction, moving consonants forward or vowels backward. A further source of error is incomplete sorting of the transformed letters. Writing all intermediate steps clearly and following the rule for each category of letter ensures accuracy in such transformation problems.

Final Answer:
In the final alphabetically arranged sequence, the letter that is fourth from the right is J.