The state of a process after it encounters an $I/O$ instruction is?
ans should be waiting (blocked)so b is true
it can be ready or Suspended wait.
A process that is blocked on some event (such as I/O operation completion or a signal) Here A process which need I/O operation moves to waiting state and blocks their till its I/O completion Then moves to ready state.
PS: The question seems to ignore non-blocking IO calls like printf
ans is (a)