If \({\rm{G}}\left( {\rm{x}} \right) = \sqrt {(25 - {{\rm{x}}^2}} \) then what is \(\mathop {\lim }\limits_{{\rm{x}} \to 1} \frac{{{\rm{G}}\left( {\rm{x}} \right) - {\rm{G}}\left( 1 \right)}}{{{\rm{x}} - 1}}{\rm{\;}}\)equal to?
1
\(- \frac{1}{{2\sqrt 6 {\rm{\;\;}}}}\)
2
\(\frac{1}{5}\)
3
\(- \frac{1}{{\sqrt 6 }}\)
4
\(\frac{1}{{\sqrt 6 }}\)