If $G(x)=-\sqrt{25-x^2}$ then $\lim\limits_{x \to 1}\large\frac{G(x)-G(1)}{x-1}$ has the value

Question

$(a)\;1/24\qquad(b)\;1/5\qquad(c)\;-\sqrt{24}\qquad(d)\;None\;of\;these$