If x=y and the sequences x,a1,a2,y and x,b1,b2,b3,y each are in arithmetic progression, then (a2−a1)/(b2−b1) equals<spanclass=′latex−bold′>(A)</span>32<spanclass=′latex−bold′>(B)</span>43<spanclass=′latex−bold′>(C)</span>1<spanclass=′latex−bold′>(D)</span>34<spanclass=′latex−bold′>(E)</span>23