Consider the following statements about process state transitions for a system using preemptive scheduling. I. A running process can move to ready state. II. A ready process can move to running state. III. A blocked process can move to running state. IV. A blocked process can move to ready state. Which of the above statements are TRUE?

Let us analyze each statement based on standard operating system process state transitions under preemptive scheduling:

1. Statement I is TRUE: In a preemptive scheduling environment, a running process can be preempted (e.g., due to a timer interrupt when its time quantum expires, or when a higher-priority process arrives) and moved back to the ready state.

2. Statement II is TRUE: When the CPU scheduler selects a process from the ready queue (scheduler dispatch), the process transitions from the ready state to the running state.

3. Statement III is FALSE: A blocked (or waiting) process cannot transition directly to the running state. When its pending I/O or event completes, it must first move to the ready state.

4. Statement IV is TRUE: When the I/O operation or requested event completes, a process in the blocked (waiting) state transitions to the ready state.

Thus, statements I, II, and IV only are TRUE, which corresponds to option C.