Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories? `x + y , 1000, x + x^2 + x^3 + x4 , 7 + y + 5x, 2y - 3y^2, 2y - 3y^2 + 4y^3, 5x -4y + 3xy, 4z - 15z^2, ab + bc +cd + da, pqr, p^2q + pq^2, 2p + 2q`