If $$\phi(x) = \dfrac{1}{\sqrt{x}} \int_{\pi/4}^{x} \left(4\sqrt{2}\sin t - 3\phi'(t)\right) dt$$, $$x > 0$$ then $$\phi'\left(\dfrac{\pi}{4}\right)$$ is equal to ______.

A

$$\frac{4}{6+\sqrt{\pi}}$$

B

$$\frac{8}{6+\sqrt{\pi}}$$

C

$$\frac{8}{ \sqrt{\pi}}$$

D

$$\frac{4}{6-\sqrt{\pi}}$$