Find each function value and the limit for $f(x)=\frac{15-7x^2}{4+x^2}.$ Use $-$ or $$ where appropriate.

$($A$)f(-10)$

$($B$)f(-20)$

$($C$)\underset{x-}{lim}f(x)$

$($A$)f(-10)=$

$($Round to the nearest thousandth as needed.$)$

$($B$)f(-20)=$

$($Round to the nearest thousandth as needed.$)$

$($C$)$ Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

A$.\underset{x-}{lim}\frac{15-7x^2}{4+x^2}=($Type an exact answer.$)$

B$.$ The limit does not exist and is neither $-$ nor $.$