Answer: Choice C) 211
When it comes to prime numbers, you either have to memorize or have a table handy. There is no quick way to check if a number is prime other than dividing by the primes smaller than it and seeing if you have a factor or not. For example, the number 99 is not prime because 3 is a factor (3 is prime). Another example: 143 is not prime because 143 = 11*13
