Determine whether the following pair of lines is parallel, intersects at a single point, or is skew. If the lines are parallel, determine whether they are the same line $($and thus intersect at all points$).$ lines intersect at a single point, determine the point of intersection.

$r=($:$1,2,3$:$)+t($:$4,-6,2$:$)$

$R=($:$21,6,19$:$)+s($:$5,1,4$:$)$

Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice.

A$.$ The lines intersect at the single point $$

$,.($Simplify your answers.$)$

B$.$ The lines are parallel.

C$.$ The lines are skew.

D$.$ The lines intersect at all points on the line $r(t).$