Which of the following statements about operating system kernels are true?

A. Preemptive scheduling allows the kernel’s thread manager to run applications in a way that helps avoid fate sharing.

B. The kernel serves as a trusted intermediary between programs running on the same computer.

C. In an operating system that provides virtual memory, the kernel must be invoked to resolve every memory reference.

D. When a kernel switches a processor from one application to another, the target application sets the page-map address register appropriately after it is running in user space.