The correct option is B 4
Prime numbers have exactly two factors, 1 and the number itself.
Factors of 2: 1, and 2
Factors of 3: 1, and 3
Factors of 4: 1, 2, and 4
Factors of 5: 1, and 5
Factors of 6: 1, 2, 3, and 6
Factors of 7: 1, and 7
Factors of 8: 1, 2, 4, and 8
Factors of 9: 1, 3, and 9
Prime numbers are: 2, 3, 5, and 7
Count = 4