Let ABC be an equilateral triangle. Extend side AB beyond B to a point B′ so that BB′=3AB. Similarly, extend side BC beyond C to a point C′ so that CC′=3BC, and extend side CA beyond A to a point A′ so that AA′=3CA. What is the ratio of the area of △A′B′C′ to the area of △ABC?<spanclass=′latex−bold′>(A)</span>9:1<spanclass=′latex−bold′>(B)</span>16:1<spanclass=′latex−bold′>(C)</span>25:1<spanclass=′latex−bold′>(D)</span>36:1<spanclass=′latex−bold′>(E)</span>37:1