Use the Gram-Schmidt process to find the orthonormal basis of $U$: $\mathbf{t}_1 = \left[\frac{1}{2}, -\frac{1}{2}, -\frac{1}{2}, \frac{1}{2}\right]^T$, $\mathbf{t}_2 = [m, n, p, q]^T$, $\mathbf{t}_3 = [r, s, x, y]^T$. $D = \left(\mathrm{Round}\left\{\frac{1}{n^2 s^2}\right\}\right) \% 5$. What is $D$? (% is the modulo operation. Round{z} rounds z to the nearest integer.)