Which of the following must be true?
1) Every prime number greater than 5 can be written as either as 7n+1 or 7n-1
2) Every prime number greater than 5 can be written as 4n+1 or 4n-1
3) Every number greater than 5 of the form 7n+1 or 7n-1 is a prime number. Select the correct option.
A) 1,2,3  B) 2,3  C) only 2  D) only 1  E) 1,2
Every prime number greater than 3 can be written in the form of 7n+1 or 7n-1 where n is an integer. So 1 can be possible.   3. This is not possible as 2 and 3 are being prime , we can't write then in the form of 7n+1 or 7n-1.   1,2
<result>E</result>
Which of the following must be true?
1) Every prime number greater than 5 can be written as either as 7n+1 or 7n-1
2) Every prime number greater than 5 can be written as 4n+1 or 4n-1
3) Every number greater than 5 of the form 7n+1 or 7n-1 is a prime number.