What does poles in unit circles center mean?
If you have $N$ poles at $z=0$ this means that your transfer function has the form
$$H(z)=\frac{P(z)}{z^N}\tag{1}$$
where $P(z)$ is a polynomial. What does this tell you about the filter type? (Hint: write $H(z)$ as a sum of positive and negative powers of $z$).