Point P is taken interior to a square with side-length a and such that is it equally distant from two consecutive vertices and from the side opposite these vertices. If d represents the common distance, then d equals:
<spanclass=′latex−bold′>(A)</span>53a<spanclass=′latex−bold′>(B)</span>85a<spanclass=′latex−bold′>(C)</span>83a<spanclass=′latex−bold′>(D)</span>2a2<spanclass=′latex−bold′>(E)</span>2a