This problem concerns the ring Z[x] of polynomials with integer coefficients. (a) Is the principal ideal (x) = {x · p(x) : p(x) ∈ Z[x]} a maximal ideal? a prime ideal? both? neither? Justify your answer. (b) Show that I = {f(x) ∈ Z[x] : f(0) is even} is an ideal of Z[x]. (c) Is the ideal I in (b) a principal ideal? If so, give a generating polynomial; if not, explain clearly why not. (d) Reflecting on your answers above, comment briefly on the following assertions: • In any integral domain R, all maximal ideals are prime. • In any integral domain R, all prime ideals are maximal. • If R is a PID, then so is the polynomial ring R[x].