Suppose a soil in a has three horizons darkened at the surface by OC, named Ap1, Ap2, and Bt1, each of 15 cm thickness, and all three have dark colors moist of 10YR 3/3. If the base saturations by the appropriate method are 60, 55, and 45, what is the epipedon? Now suppose the base saturation is 60, 45, and 40, what is the epipedon?