Determine the concavity of f(x) = x3 - 24x2 + 6x + 18 and identify any points of inflection.
◦ concave upwards on (- ∞, 8), downwards on (8, ∞); inflection at x = 8
◦ concave upwards on (- ∞, -8), downwards on (-8, ∞); inflection at x = -8
◦ concave downwards on (-∞, 8), upwards on (8, ∞); inflection at x = 8
◦ concave downwards on (-∞, -8), upwards on (-8, ∞); inflection at x = -8
◦ concave upwards on (-∞, ∞); no inflection points