Nate measured the side length and perimeter or five equilateral triangles, as shown in the table below. Which of the following best explains why these vales are or are not in a proportional relationship? A They are proportional, because the ratio of perimeter to side lengths is always 3:1. B They are proportional, because the perimeter always increases by the same amount from column to column. C They are not proportional, because the side length increases by varying amounts from column to column. D They are not proportional, because the difference between side length and perimeter is different for each column