Find the extreme values (absolute and local) of the function over its natural domain: A: f(x) = 6x2 - x3, and x E [-1, 6]. B: g(x) = (x - 1)2(x - 3)2, and x E [1, 3] C: h(x) = cos(2xx), and x E [0, 1]. D: k(x) = e* (sin x) and x E [0, it]