Let $f(x,y)$ be a function that has $(9,5)$ as a critical point. We determine that $f_x(9,5)=6,f_y(9,5)=3,$ and $f_{yy}(9,5)=-4.$ What does the D $-$sest lell us about the function $?$

A$.$ Thas a relative maximum at $(9,5).$

B$.$ thas a relative minimum at $(9\mathrm{.}5).$

C$.$ thas a saddle point at $(9,5).$

D$.$ The answer cannot be determined from the information given.