Indefinite blocking is the another term for starvation .. Meaning that a process may never be allowed to execute in the running state..This happens in SRTF and priority scheduling ..
This can be explained as :
As soon as the process having shortest remaining time is there , then another process of shorter time burst may arrive , or equivalently of higher priority may arrive in the ready queue..Hence starvation is possible in case of both of these..
As opposed this , the order in FCFS is defined already by the order in which they arrive in ready queue and hence ready state ..Same is the case of round robin algorithm..
Hence both B) and D) are correct answers..