Question

Which of the polynomials has all real solutions and no imaginary solutions?
O f(x) = x5 - 2x4 - 10x³ + 16x² + 25x - 30
O f(x) = x5 - 2x4 - 8x³ + 20x² + 15x - 50
O f(x) = x5 - 2x4 - 8x³ - 20x² - 65x - 50
O f(x) = x6 - 4x5 - 4x4 + 36x³-25x² 80x + 100