What is the largest possible area of an isosceles trapezoid in which the largest side is 13 and the perimeter is 28?<spanclass=′latex−bold′>(A)</span>13<spanclass=′latex−bold′>(B)</span>24<spanclass=′latex−bold′>(C)</span>27<spanclass=′latex−bold′>(D)</span>28<spanclass=′latex−bold′>(E)</span>30