Which one of the following groups of numbers includes all prime numbers? A. 7, 17, 63, 67 B. 3, 11, 23, 31 C. 1, 3, 11, 23 D. 2, 3, 5, 15

The prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

A.

7 - is a prime number

17 - is a prime number

63 - is not a prime number because 63 = 3 * 21

B.

3 - is a prime number

11 - is a prime number

23 - is a prime number

31 - is a prime number

C.

1 - is not a prime number

D.

2 - is a prime number

3 - is a prime number

5 - is a prime number

15 - is not a prime number because 15 = 3 * 5