Determine the following limit$.$

$\underset{x-}{lim}(4x^7-8x^6+1)$

Select the correct choice below and, if necessary, fill in the answer box to complete $y$

A$.\underset{x-}{lim}(4x^7-8x^6+1)=$

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