BB1 connects to R1 which connects to R2 all three in RIP network. R2 connects to OSPF domain.
R1 and R2 are connected over serial interfaces in frame-relay.
Since split-horizon is disabled by default on frame-relay interfaces for RIP, is there any reason you would enable split-horizon on the serial interfaces between R1 and R2 in this configuration?
I can't find one.