A research article examining a possible relationship between the dimensions (length ratio) of people's faces and their corresponding attractiveness provided the graph below and the trend line equation, , where is Thurstonian attractiveness and L is the length ratio of the person's face. a parabolic function showing ther relationship between length ratio (eye to mouth distance/ face length) x- axis and Thurstonian attractiveness (y-axis). The graph shows a parabolic function facing down. The equation for the function is TA = -51L^2 +37L -6. What type of trendline did these researchers use in the graph shown above? Group of answer choices A linear function where the input is and the output is . An exponential function where the input is and the output is A quadratic function where the input is and the output is . An exponential function where the input is and the output is . A quadratic function where the input is and the output is