On the bottom edge of a rectangular advertisement board, two points are marked to divide this edge into three equal parts, and a lighting lamp is placed at each of these points. When on, each lamp illuminates a triangular region on the board as shown in the figure, with one vertex at the point where the lamp is located and the other two vertices at the endpoints of the board's top edge. According to this, the area of the advertisement board that is not illuminated when only one lamp is on is how many times the area that is not illuminated when both lamps are on? A) $\frac{4}{3}$ B) $\frac{5}{4}$ C) $\frac{6}{5}$ D) $\frac{7}{6}$ E) $\frac{8}{7}$
On the bottom edge of a rectangular advertisement board, two points are marked to divide this edge into three equal parts, and a lighting lamp is placed at each of these points. When on, each lamp illuminates a triangular region on the board as shown in the figure, with one vertex at the point where the lamp is located and the other two vertices at the endpoints of the board's top edge.
According to this, the area of the advertisement board that is not illuminated when only one lamp is on is how many times the area that is not illuminated when both lamps are on?
A) $\frac{4}{3}$
B) $\frac{5}{4}$
C) $\frac{6}{5}$
D) $\frac{7}{6}$
E) $\frac{8}{7}$