$\mathrm{z}_{1}$ and $\mathrm{z}_{2}$ are two complex numbers in which $\mathrm{z}_{2}$ is not uni-modular. If $\frac{2 \mathrm{t}_{2}^{2}}{\mathrm{z}_{1}-2 \mathrm{z}_{2}}$ is unimodular, $\left|\mathrm{z}_{1}\right|$ is equal to
(a) $\underline{1}$
(b) 2
(c) 3
(d) 4