If a polynomial f(x) over the real numbers has the complex numbers 2 + i and 1 - i as roots, then f(x) could be
(A)x^3 + 5x^2 + 4x + 1 (B)x^4 - 6x^3 + 15x^2 - 18x + 10 (C)x^3 - x^2 + 4x + 1 (D)x^4 + 7x^2 + 10
B