B) is true . bcoz if round trip time is greater than time out , then how will u be able to calculate the RTT.
So , to calculate RTT , it must be less than Timeout..
Note :- if RTT>time out (Which is disadvantage of jacobsan algo then Karn modification is used )...
Karn modification :- if ack did not come till timeout, then packet will be retransmitted with twice of previous timeout...
Anyway RTT must be less than or equal to timeout.......