Classification – Prime vs composite/square: three numbers are composite or perfect squares; one is a prime. Identify the odd one out. Options: 88, 97, 132, 121.

Introduction / Context:
Number classification often contrasts primes with composites (including perfect squares). Spotting the sole prime quickly identifies the outlier.

Given Data / Assumptions:

• 88: composite (2^3 * 11).
• 132: composite (2^2 * 3 * 11).
• 121: perfect square (11^2), hence composite.
• 97: prime (no divisors other than 1 and 97).

Concept / Approach:
Classify each as prime vs composite. A perfect square automatically belongs to the composite class (except 1, which is neither prime nor composite).

Step-by-Step Solution:
Test 88 → composite.Test 132 → composite.Test 121 → 11^2 → composite.Test 97 → no small prime factors; prime.

Verification / Alternative check:
Divisibility checks confirm 97 is not divisible by primes ≤ 9 (2,3,5,7), so it is prime.

Why Other Options Are Wrong:
88/132/121: All are composite (121 is square of 11).

Common Pitfalls:
Mistaking 121 as prime due to identical digits; it is 11 * 11.

Final Answer:
97