From the given words, select the word that cannot be formed from the letters of the word JAUNTILY, using each letter at most once.

Introduction / Context:
Word-formation questions test your ability to check whether a given word can be built from the letters of another word, with each letter used at most as many times as it appears in the original. Here the base word is JAUNTILY, and you must find which of the options cannot be formed using its letters.

Given Data / Assumptions:

• Base word: JAUNTILY.
• Available letters: J, A, U, N, T, I, L, Y (each appears exactly once).
• Options: NEATLY, AUNTY, JAUNT, UNITY.
• Each option must be evaluated by checking letter availability and frequency.

Concept / Approach:
We list the letters of the base word and their counts. Then, for each option, we check whether every required letter exists in the base word and whether the number of times it is needed does not exceed the available count. If any required letter is missing or needed more times than available, that option cannot be formed from the base word.

Step-by-Step Solution:
Step 1: List letters of JAUNTILY. Letters: J, A, U, N, T, I, L, Y. Each letter appears once. Step 2: Check option NEATLY. Letters of NEATLY: N, E, A, T, L, Y. We compare: N, A, T, L and Y are present in JAUNTILY. However, the letter E does not appear in JAUNTILY at all. Therefore NEATLY cannot be formed. Step 3: Check option AUNTY. Letters: A, U, N, T, Y. All of these letters are present in JAUNTILY, each required only once. Hence AUNTY can be formed. Step 4: Check option JAUNT. Letters: J, A, U, N, T. Every letter appears in JAUNTILY at least once. Each is needed only once, so JAUNT can be formed. Step 5: Check option UNITY. Letters: U, N, I, T, Y. Again, each appears in JAUNTILY only once and is used once, so UNITY can be formed.

Verification / Alternative check:
Only NEATLY requires the letter E, which is completely absent from the base word. All other options use only letters J, A, U, N, T, I, L and Y, no more than once each. Thus only one option fails the letter-availability test, which makes our conclusion robust.

Why Other Options Are Wrong (i.e., they can be formed):
Option B (AUNTY): Uses A, U, N, T and Y, all present in the base word with sufficient frequency. Option C (JAUNT): Uses J, A, U, N and T, all present in the base word. Option D (UNITY): Uses U, N, I, T and Y, again all present in the base word.

Common Pitfalls:
A typical mistake is to check only whether the letters look similar visually without explicitly checking each letter and its count. Another common issue is forgetting that each letter in the base word has a maximum multiplicity. Even if the letter exists, it might be required more times than it appears. Always list out letters carefully and perform a one-to-one comparison.

Final Answer:
The word that cannot be formed from the letters of JAUNTILY is NEATLY, which corresponds to option A.