• # question_answer Which one of the following is a prime number? A)  161   B)  171   C)  173     D)  221

(A) $161<{{(13)}^{2}}$ If 161 is a prime number, then this is not divisible by any of the numbers 2, 3, 5, 7 and 11, but 161 is divisible by 7. Hence 161 is not a prime number. (B)                $171<{{(14)}^{2}}$ For prime number 171, is not divisible by any of the number 2 3, 5, 7, 1113. But it is divisible by 3. Hence, 171 is not a prime number. (C)                  $173<{{(14)}^{2}}$ For prime number 173 is not divisible by any of the numbers 2 3, 5, 7, 11 and 13. Hence, 173 is a prime number. (D)                  $221<{{(15)}^{2}}$ For prime number 221, is not divisible by any of the numbers 2 3, 5, 7, 11 and 13. But it is divisible by 13. Hence, 221 is not a prime number.