1.1 Which of these set of numbers are prime numbers? A) \( 1,2,5 \) B) \( 2,4,6 \) C) \( 2,3,5 \) D) \( 5,7,9 \)

Let's analyze each option step by step. 1. **Option A: \(1, 2, 5\)** - \(1\) is not a prime number (by definition, primes are greater than 1). - \(2\) is prime. - \(5\) is prime. - Since \(1\) is not prime, this set is not entirely composed of prime numbers. 2. **Option B: \(2, 4, 6\)** - \(2\) is prime. - \(4\) is not prime because \(4 = 2 \times 2\). - \(6\) is not prime because \(6 = 2 \times 3\). - This set contains non-prime numbers. 3. **Option C: \(2, 3, 5\)** - \(2\) is prime. - \(3\) is prime. - \(5\) is prime. - All numbers in this set are prime numbers. 4. **Option D: \(5, 7, 9\)** - \(5\) is prime. - \(7\) is prime. - \(9\) is not prime because \(9 = 3 \times 3\). - This set contains a non-prime number. **Conclusion:** The set that contains only prime numbers is Option C: \(2, 3, 5\).