Suppose $g$ is a collision resistant hash function that takes an arbitrary bitstring as input and produces an $n-$bit message digest. Define a hash function $h$ as follows:

$h(x)=\{\begin{array}{ccc}0||x& ifxis\text{a}\text{b}\text{i}\text{t}\text{s}\text{t}\text{r}\text{i}\text{n}\text{g}of\text{l}\text{e}\text{n}\text{g}\text{t}\text{h}& n\\ 1||g(x)& \text{o}\text{t}\text{h}\text{e}\text{r}\text{w}\text{i}\text{s}\text{e}& \end{array}$

a$.$ Is $h$ collision resistant?

b$.$ Is $h$ preimage resistant?