\(\begin{pmatrix} -2 & 1 \\ 2 & 3 \end{pmatrix}\) + \(\begin{pmatrix}p & q \\ r & s\end{pmatrix}\) = \(\begin{pmatrix} 1 & 0 \\0 & 1 \end{pmatrix}\). What is the value of r?

• A.-\(\frac{1}{8}\)
• B.\(\frac{3}{8}\)
• C.\(\frac{5}{8}\)
• D.\(\frac{1}{4}\)
• E.