Suppose the second derivative of f(x) is given by f"(x) = 3(x2 + 16) Determine the intervals of concavity of f(x). (x2 - 49)7 Of(x) is concave up on (-co,-7) U (7,0) and concave down on (-7,7). O f(x) is concave up on (-co,-4) U (4,00) and concave down on (-4,4). O f(x) is concave up on (-0,7) and concave down on (7,co). O f(x) is concave up on (-7,7) and concave down on (-co,-7) U (7,00). O f(x) is concave up on (-4,4) and concave down on (-co, -4) U (4,00)