Let $A=R-\{3\}$ and $B=R-\{1\}$. Consider the function $f:A \to B$ defined by $f(x)=\large\frac {x-2}{ x-3}$. Is $f$ one-one and onto?

Question

$\begin{array}{1 1} \text{one-one and onto} \\ \text{neither one -one nor onto} \\ \text{only one-one} \\ \text{only onto}\end{array}$