In each case below, select the best answer to the question. (a) The graph of f(x) is shown below. What is the sign of the second derivative of f(x) ? 10 1I (b) The formula for g is given by 900 = ax2 + bx + 503 for some positive constants a and b. What is the sign of the second derivative of 900 ? (c) Some values of a function 5 are shown in the table below. What is the sign of the second derivative of 500 ? I x I 5 I 6 I 7 I 8 I 500 I43 I44 I46 I49 (d) Some values of the derivative of a function T are shown in the table below. What is the sign of the second derivative of T(x) ? IfITITITIT I T'(X) I99 I94 I90 I87