Which of the following best describes the blueline in the image below?A. The perpendicular bisector of segment ABB. The line that goes through the midpoint of segment ABC. The line through point that is perpendicular to segment AB

From the figure, we can only be sure about two things. The line passes through point C, and it makes a right angle with the segment AB, therefore, they are perpendicular to each other.
Thus, the answer is
The line through C point that is perpendicular to segment AB.