f: $\{0,133\{0,133$

f$($x$)$ is obtained by removing the second bit from x and placing the bit at the end of the

string. For example, f$(101)=110.$

Select the correct description of the function f$.$

One$-$to$-$one and onto

One$-$to$-$one but not onto

Onto but not one$-$to$-$one

Neither one$-$to$-$one nor onto