Let
P−ABC
be a tetrahedron whose edges have a length of 6 . If points
D,E,F
are the barycenter of triangles
△PAB,△PBC,△PAC
respectively, then the volume of the trigonal pyramid
P−DEF
is ( ).





























Let
P−ABC
be a tetrahedron whose edges have a length of 6 . If points
D,E,F
are the barycenter of triangles
△PAB,△PBC,△PAC
respectively, then the volume of the trigonal pyramid
P−DEF
is ( ). (A)
3
4
2




(B)
3
2




(C)
2
3
2




(D)
2
2


(E)
4
2