Find the number of functions defined on positive real numbers such that f\left(1\right) \equal{} 1 and for every x,y∈ℜ, f\left(x^{2} y^{2} \right) \equal{} f\left(x^{4} \plus{} y^{4} \right). <spanclass=′latex−bold′>(A)</span>0<spanclass=′latex−bold′>(B)</span>1<spanclass=′latex−bold′>(C)</span>2<spanclass=′latex−bold′>(D)</span>4<spanclass=′latex−bold′>(E)</span>Infinitely many