There are three coplanar parallel lines. If any p points are taken on each of the lines, the maximum umber of triangles with vertices at these points is

• A

  ${ }^{3\mathrm{p}}{\mathrm{C}}_3$

• B

  ${\mathrm{p}}^2(\mathrm{p}-1)$

• C

  ${\mathrm{p}}^2(4\mathrm{p}-1)$

• D

  ${\mathrm{p}}^2(4\mathrm{p}-3)$