From the given alternative words, select the single word that can be formed using the letters of the word SOMNAMBULISM.

Introduction / Context:
This question belongs to the family of letter formation problems in verbal reasoning. You are given a base word and must decide which of the options can or cannot be formed from its letters. Here, the base word is SOMNAMBULISM and you must select the one option that can be formed by rearranging some or all of its letters without adding any new letters or repeating letters more than their available frequency.

Given Data / Assumptions:

• Base word: SOMNAMBULISM.
• Available letter multiset: S, O, M, N, A, M, B, U, L, I, S, M.
• Option A: NAMES.
• Option B: BASALT.
• Option C: SOUL.
• Option D: BIOME.
• Assumption: Each letter can be used at most as many times as it occurs in SOMNAMBULISM, and no extra letters may be introduced.

Concept / Approach:
The fundamental idea is to count letters in the base word and then check every option against these counts. An option is valid if every letter in it exists in the base word and the quantity of each letter in the option does not exceed what is present in the base word. If any option requires a missing letter, it is immediately invalid. If it requires a letter more times than it appears in the base word, it is also invalid. Exactly one option here meets all the constraints and that option is the correct answer.

Step-by-Step Solution:
Step 1: Count letters in SOMNAMBULISM: A(1), B(1), I(1), L(1), M(3), N(1), O(1), S(2), U(1).Step 2: Check NAMES: N, A, M, E, S. The base word does not contain the letter E, so NAMES cannot be formed.Step 3: Check BASALT: B, A, S, A, L, T. This needs two As and one T. The base word has only one A and no T, so BASALT cannot be formed.Step 4: Check SOUL: S, O, U, L. All these letters appear in the base word with at least the required frequency (S2, O1, U1, L1), so SOUL can be formed.Step 5: Check BIOME: B, I, O, M, E. While B, I, O, and M are available, the letter E does not appear in SOMNAMBULISM, so BIOME cannot be formed.

Verification / Alternative check:
A quick scan of SOMNAMBULISM shows that letters E and T are completely absent. Any option that contains E or T must therefore be invalid. NAMES and BIOME both include E, and BASALT includes both E and T, so they are impossible. SOUL does not introduce any missing letters and uses each of S, O, U, and L only once, which is within the available counts. This alternative check supports the conclusion that SOUL is the only constructible word from the given options.

Why Other Options Are Wrong:
Option NAMES is wrong because it includes the letter E, which the base word does not contain.Option BASALT is wrong because it needs two As and the letter T, but the base word has only one A and no T at all.Option BIOME is wrong because it also requires the missing letter E, even though the other letters do appear in the base word.

Common Pitfalls:
Students often focus only on whether most letters match and forget to check every single letter, especially vowels like E or consonants like T. Another common mistake is failing to account for repeated letters, such as options needing two occurrences of a letter when only one is available. To avoid these issues, always list out the base word letters with their frequencies and systematically compare each option rather than relying on quick visual matching.

Final Answer:
The only word that can be formed from the letters of SOMNAMBULISM is SOUL.