Draw a circle having centre at  P and radius d meters. 
If the point Q  lies inside the circle then the lines drawn through the point P at a distance of d units is zero.
If the point Q  lies on the circle then the lines drawn through the point P at a distance of d units is one.
If the point Q  lies outside the circle then the lines drawn through the point P at a distance of d units is two. 
Here,  $\mathrm{PQ}>\mathrm{d}$
It means the point Q  lies outside the circle
Therefore, the number of lines drawn through the point P at a distance of d units is two