How many four-digit integers abcd, with a=0, have the property that the three two-digit integers ab<bc<cd form an increasing arithmetic sequence? One such number is 4692, where a=4, b=6, c=9, and d=2.<spanclass=′latex−bold′>(A)</span>9<spanclass=′latex−bold′>(B)</span>15<spanclass=′latex−bold′>(C)</span>16<spanclass=′latex−bold′>(D)</span>17<spanclass=′latex−bold′>(E)</span>20