Let k be an integer. If k + 1 is divisible by 3, then the integer k is defined as "Type A". If an integer is "Type A", then the expression k² + 1 results in a prime number.
For which of the following values of k is the expression k² + 1 guaranteed to be a prime number based on the rules?
k = 3
k = 4
k = 5
k = 6
