Answer: A
Explanation: A non-attributional negative statement is a type of statement that attributes a person's negative qualities or actions to their inherent characteristics, rather than to external factors. In this case, the statement "I guess you are just not very good at math" attributes the child's poor performance on the math test to their inherent lack of ability in math, rather than to external factors such as a lack of effort or a lack of understanding. This type of statement can be harmful because it can lead the child to believe that they are inherently bad at math, which can affect their motivation and confidence. It is important for parents to consider external factors when responding to children's poor performance and to provide support and encouragement rather than attributing their struggles to inherent characteristics.