The correct option is option (c) $3,-1$
Let $f(x)=x^{2}-2 x-3=0$
$=x^{2}-3 x+x-3=0$
$=x(x-3)+1(x-3)=0$
$=(x-3)(x+1)=0$
$\Rightarrow \mathrm{x}=3$ or $\mathrm{x}=-1$
The correct option is option (c) $3,-1$
Let $f(x)=x^{2}-2 x-3=0$
$=x^{2}-3 x+x-3=0$
$=x(x-3)+1(x-3)=0$
$=(x-3)(x+1)=0$
$\Rightarrow \mathrm{x}=3$ or $\mathrm{x}=-1$