If 3p+34=90, 2r+44=76, and 53+6s=1421, what is the product of p, r, and s?<spanclass=′latex−bold′>(A)</span>27<spanclass=′latex−bold′>(B)</span>40<spanclass=′latex−bold′>(C)</span>50<spanclass=′latex−bold′>(D)</span>70<spanclass=′latex−bold′>(E)</span>90