Question 1:

a. Without interrupts, the kernel cannot intentionally transfer control from a user program to the kernel. Is it true or False?

b. The processor can be switched to kernel mode during execution of a user process, if the user process issues a system call. Is it true or False?

c. A system call is a function linked into a user-mode program that executes a "transition to kernel mode" instruction, then begins to execute arbitrary code with kernel privileges. Is it true or false?

d. Every user-level thread must have a unique kernel-level thread in order to facilitate multithreading? I think this is false, correct?