Step 1: Understand the process creation sequence.
- **B**: The process creation starts with the **fork()** system call, which creates a new child process.
- **A**: After the process is created, the **exec()** system call is used by the child process to replace its memory space with a new program.
- **D**: The **exec()** system call loads a new binary file into memory and starts execution.
- **C**: The parent process can then create more children or call the **wait()** system call to wait for the child process to finish execution.
Step 2: Conclusion.
Thus, the correct order is **B, A, D, C**.
Find the least upper bound and greatest lower bound of \( S = \{X, Y, Z\} \) if they exist, of the poset whose Hasse diagram is shown below:
Suppose \( D_1 = (S_1, \Sigma, q_1, F_1, \delta_1) \) and \( D_2 = (S_2, \Sigma, q_2, F_2, \delta_2) \) are finite automata accepting languages \( L_1 \) and \( L_2 \), respectively. Then, which of the following languages will also be accepted by the finite automata:
(A) \( L_1 \cup L_2 \)
(B) \( L_1 \cap L_2 \)
(C) \( L_1 - L_2 \)
(D) \( L_2 - L_1 \)
Choose the correct answer from the options given below: