The point P is the intersection of the straight line joining the points Q(2,3,5) and R(1, -1, 4) with the plane 5x - 4y - z = 1. If S is the foot of the perpendicular drawn from the point 7(2, 1, 4) to QR, then the length of the line segment PS is

A

$$\frac{1}{\sqrt{2}}$$

B

$$\sqrt{2}$$

C

2

D

$$2\sqrt{2}$$