which of the following RTS threshold and CWmin settings would be correct for the non-root bridges?

When optimizing a standalone point-to-multipoint bridge installation with eight non-root bridges, which of the following RTS threshold and CWmin settings would be correct for the non-root bridges?

A.
RTS threshold=4000, CWmin=3

B.
RTS threshold=1, CWmin=4

C.
RTS threshold=4000, CWmin=5

D.
RTS threshold=1, CWmin=5