Which of the following is true?
A. 5 is a prime number becuase one and five are its only factors
B. 19 is a composite number because it is only divisable by one and itself
C. 12 is a prime number because it is divisable by 4
D. 25 is a composite number because 52 is a prime number

Question

Which of the following is true? 
A. 5 is a prime number becuase one and five are its only factors 
B. 19 is a composite number because it is only divisable by one and itself
C. 12 is a prime number because it is divisable by 4 
D. 25 is a composite number because 52 is a prime number

matt101 · Answer

A

Prime numbers can only be divided by 1 and themselves, while composite numbers have other factors as well. This is why A is correct. The others are wrong because 19 is prime, 12 is composite, and 25 is composite but not for the reason the answer says.