A set-builder notation is a mathematical notation for describing a set by enumerating its elements or stating the properties that its members must satisfy. In your case, the set builder notation {x l x > } means that the set consists of all elements that are greater than.
Consider number line. Plot the point as unfilled circle that goes after > sigh and shade the ray that goes from this point to the right. Then another way to represent this solution is
( ,∞).
Answer: correct choice is C