f:$\{0,1\}4->\{0,1\}4$f$($x$)$

is obtained from x

by replacing the last bit with $1$

$.$

For example, f$(1000)=1001$

$.$

Select the correct description of the function f

$.$

Group of answer choices

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

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

One$-$to$-$one and onto

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