What is the scalar projection of \(\vec{a}=\hat{i}-2\hat{j}+\hat{k}\) on \(\vec{b}=4\hat{i}-4\hat{j}+7\hat{k}~?\)

• A. \(\frac{\sqrt{6}}{9}\)
• B. 19/9
• C. 9/19
• D. \(\frac{\sqrt{6}}{19}\)