I. (12 points) Unify the followin pairs of expressions and show the most general unifiers. a) f(g(X,W), t(h(Z), b(Y), c), g(Y, Z)) and f(g(a(Y), Z), t(U, V, c), g(7, s(d)) b) q(W, d(a, ), w(Z, d(b, 8)), Y) and q(2, X), w(g(a), U), w(U, W))