what is the correct RPF path toward the multicast source from R6?

— Exhibit –

— Exhibit —
Click the Exhibit button.
Referring to the exhibit, what is the correct RPF path toward the multicast source from R6?

A.
R6-R5

B.
R6-R7-R4-R5

C.
R6-R4-R5

D.
R6-R4-R3-R2-R5