For the function shown below, find (if the quantity exists) (A) lim f(x), (B) lim f(x), (C) lim f(x), and (D) f(0). X-0 X-0 21-x2, for x so f(x ) =. 21 + x2 for x> 0 (A) Select the correct choice below and fill in any answer boxes in your choice. O A. lim f(x) = x-0 O B. The limit does not exist