A cube of cheese C={(x,y,z)∣0≤x,y,z≤1} is cut along the planes x=y, y=z and z=x. How many pieces are there? (No cheese is moved until all three cuts are made.)<spanclass=′latex−bold′>(A)</span>5<spanclass=′latex−bold′>(B)</span>6<spanclass=′latex−bold′>(C)</span>7<spanclass=′latex−bold′>(D)</span>8<spanclass=′latex−bold′>(E)</span>9