Which of the following is a composite number? a. 91 b. 139 c. 13 d. 29

A composite number is a number that's not prime. A prime number is a number who only has 2 factors (1 and itself). A composite number has multiple factors.

For example;
7 is prime, as the factors of 7 are only 1&7.
14 is composite, as there are 4 factors (more than 2); 1&14, 2&7.

91 is composite, as it has the following factor pairs; 1&91, 7&13.

139 only has 1&19, making it prime.
13 only has 1&13, making it prime.
29 only has 1&13, making it prime.

Your answer is A.) 91.

I hope this helps!

A)91 because it can be divided by 7 and 1. And a composite number is a number that can be evenly divided by other numbers beside 1 and itself.