Determine the horizontal asymptote of the function. If none exists, state that fact.

$f(x)=\frac{8x}{28x-9}$

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

A$.$ The function has two horizontal asymptotes. The top asymptote is and the bottom asymptote is $($Type equations.$)$

B$.$ The function has one horizontal asymptote, $.($Type an equation.$)$

C$.$ The function has no horizontal asymptotes.