Let statement s be the following: If an integer d, if 6/d is an integer, then d=3. Which of the following is the contrapositive?
1) If d is not equal to 3, then 6/d is not an integer
2) If d is equal to 3, then 6/d is an integer
3) If 6/d is not an integer, then d is not equal to 3
4) If 6/d is an integer, then d is equal to 3
