If \( \Phi(x) = \frac{1}{\sqrt{x}} \int_{\pi/4}^{x} \left( 4\sqrt{2}\sin t - 3\Phi'(t) \right) dt, \ x>0 \), then \( \Phi'\!\left(\frac{\pi}{4}\right) \) is equal to:
\( \frac{4}{6+\sqrt{\pi}} \)
\( \frac{8}{6+\sqrt{\pi}} \)
\( \frac{4}{6-\sqrt{\pi}} \)
\( \frac{8}{\sqrt{\pi}} \)