Calculate the successive average rates of change for the function, $H(x)$ in the table below.

$x$	12	14	16	18
$H(x)$	21.5	21.62	21.85	22.14

 
(a) The average rate of change over the interval   $12 \leq x \leq 14$ is
(Retain at least 3 decimal places in your answer.)

(b) The average rate of change over the interval   $14 \leq x \leq 16$ is
(Retain at least 3 decimal places in your answer.)

(c) The average rate of change over the interval   $16 \leq x \leq 18$ is
(Retain at least 3 decimal places in your answer.)

(d) Based your answers for the rates of change, the function $H(x)$ is
A. Concave Up
B. Concave Down
C. Neither concave up or concave down
D. Both concave up and concave down