Choose the odd number: In 11, 17, 45, and 37, three are prime numbers and one is composite. Identify the composite number.

Introduction / Context:
This classification asks you to separate a composite number from a set of primes. Spotting quick divisibility helps.

Given Data / Assumptions:

• Candidates: 11, 17, 45, 37.
• Prime = two divisors; composite = more than two.

Concept / Approach:
Check divisible-by-2, divisible-by-3 (digit-sum), and divisible-by-5 (ends with 0 or 5). Then confirm any remaining suspects with small primes.

Step-by-Step Solution:

Verification / Alternative check:
Further factorization: 45 = 3 * 3 * 5 confirms composite status.

Why Other Options Are Wrong:
11, 17, and 37 have no non-trivial divisors.

Common Pitfalls:
Overlooking the easy 5-divisibility rule for numbers ending in 5.

Final Answer:
45 is composite and is the odd number.