Which one of the following functions is analytic in the region $\mid z \mid \leq 1$ ?
1. $\frac{z^{2}-1}{z} \\$
2. $\frac{z^{2}-1}{z+2} \\$
3. $\frac{z^{2}-1}{z-0.5} \\$
4. $\frac{z^{2}-1}{z+j0.5}$