Each vowel in the word NICELY is changed to the previous letter in the English alphabet and each consonant is changed to the next letter in the English alphabet. After these changes, all the resulting letters are arranged in alphabetical order. Which letter will be fourth from the left in this new alphabetical arrangement?

Introduction / Context:
This question combines simple letter coding with alphabetical ordering. It tests the ability to carefully apply transformation rules to each character of a word and then to sort the resulting letters correctly. Such problems are common in reasoning sections of aptitude tests and help verify careful reading and attention to detail.

Given Data / Assumptions:

• Original word: NICELY.
• Vowels in the word (I and E) are changed to the previous letter in the English alphabet.
• Consonants in the word (N, C, L and Y) are changed to the next letter in the English alphabet.
• After all substitutions, the new letters are arranged in strict alphabetical order from left to right.
• We must identify the fourth letter from the left in this ordered list.

Concept / Approach:
The problem proceeds in two stages. First, perform a letter by letter transformation using the given coding rule. Second, once the new letters are obtained, arrange them alphabetically and then simply count the letters from left to right. Care must be taken not to confuse the directions of the changes for vowels and consonants.

Step-by-Step Solution:
Step 1: Identify vowels and consonants in NICELY: N, C, L and Y are consonants; I and E are vowels.Step 2: Apply the rule to each letter one by one:N (consonant) becomes O, the next letter in the alphabet.I (vowel) becomes H, the previous letter in the alphabet.C (consonant) becomes D, the next letter in the alphabet.E (vowel) becomes D, the previous letter in the alphabet.L (consonant) becomes M, the next letter.Y (consonant) becomes Z, the next letter.Step 3: The resulting multiset of letters is {O, H, D, D, M, Z}.Step 4: Arrange these letters alphabetically: D, D, H, M, O, Z.Step 5: Count from the left: first D, second D, third H, fourth M. So the fourth letter from the left is M.
Verification / Alternative check:
We can quickly recheck by listing the letters again in order and verifying that the transformations are correctly applied. A careful recount of positions in the sorted sequence confirms that after D, D and H, the next distinct letter is M in the fourth position. No other letter order yields a different result, so this is consistent.

Why Other Options Are Wrong:
J and B do not appear in the transformed set of letters at all. O and Z do appear but they are the fifth and sixth letters when sorted alphabetically, not the fourth. Therefore, among the options given, M is the only correct answer.

Common Pitfalls:
Students often invert the rule, for example moving consonants to the previous and vowels to the next letter, which leads to an incorrect set of letters and hence a wrong answer. Another common error is to forget that Y is a consonant in this context and treat it incorrectly. Finally, mistakes can occur when sorting the letters alphabetically if the set is not written out clearly.

Final Answer:
The fourth letter from the left in the final alphabetical arrangement is M.