Answer:
A. 9
Explanation:
A counterexample shows that one side is true while the other is false
x>7 and x>11
sub in the answers
9>7 and 9>11 -this is true for the first half but false for the second
5>7 and 5>11 -this is false for both
13>7 and 13>11 -this is true for both
15>7 and 15>11 -this is true for both
Answer A is correct as it proves the statement to be incorrect