Nine chairs in a row are to be occupied by six students and Professors Alpha, Beta and Gamma. These three professors arrive before the six students and decide to choose their chairs so that each professor will be between two students. In how many ways can Professors Alpha, Beta and Gamma choose their chairs?<spanclass=′latex−bold′>(A)</span>12<spanclass=′latex−bold′>(B)</span>36<spanclass=′latex−bold′>(C)</span>60<spanclass=′latex−bold′>(D)</span>84<spanclass=′latex−bold′>(E)</span>630