How many ordered pairs (p,n) are there such that (1+p)n=1+pn+np where p is a prime and n is a positive integer?<spanclass=′latex−bold′>(A)</span>5<spanclass=′latex−bold′>(B)</span>2<spanclass=′latex−bold′>(C)</span>1<spanclass=′latex−bold′>(D)</span>0<spanclass=′latex−bold′>(E)</span>None of the preceding