Let x,y, and z be three positive real numbers whose sum is 1. If no one of these numbers is more than twice any other, then the minimum possible value of the product xyz is
<spanclass=′latex−bold′>(A)</span>321<spanclass=′latex−bold′>(B)</span>361<spanclass=′latex−bold′>(C)</span>1254<spanclass=′latex−bold′>(D)</span>1271<spanclass=′latex−bold′>(E)</span>none of these