If a,b,n are positive integers, number of solutions of the equaition a^2 \plus{} b^4 \equal{} 5^n is <spanclass=′latex−bold′>(A)</span>1<spanclass=′latex−bold′>(B)</span>2<spanclass=′latex−bold′>(C)</span>3<spanclass=′latex−bold′>(D)</span>4<spanclass=′latex−bold′>(E)</span>Infinitely many