Question

Which of the following groups of numbers are all prime numbers? A. 3, 11, 23, 31 B. 2, 3, 5, 9 C. 2, 5, 15, 19 D. 7, 17, 29, 49

Answer 1

I think it is A. or D

Answer 2

A because 9 is not prime in answer B, 15 is not prime in answer C, and 49 is not prime in answer D. So the correct answer is A.