How many polynomial functions f of degree ≥1 satisfy
f(x2)=[f(x)]2=f(f(x))?<spanclass=′latex−bold′>(A)</span>0<spanclass=′latex−bold′>(B)</span>1<spanclass=′latex−bold′>(C)</span>2<spanclass=′latex−bold′>(D)</span>finitely many but more than 2<spanclass=′latex−bold′>(E)</span>infinitely many