What is the minimum value of ab+cd, if ab+cd=ef+gh where a,b,c,d,e,f,g,h are distinct positive integers?<spanclass=′latex−bold′>(A)</span>34<spanclass=′latex−bold′>(B)</span>33<spanclass=′latex−bold′>(C)</span>32<spanclass=′latex−bold′>(D)</span>31<spanclass=′latex−bold′>(E)</span>30