5) Which of the following statements about operating system structure is correct? A) Windows XP is designed with the layered approach. B) In the loadable kernel module approach, each layer invokes operations on lower-level layers, simplifying the construction and debugging. C) It is easy to add new services to the microkernel-based operating system without modifying the kernel, greatly improving the performance of microkernels. D) Microkernel provides communication between the client program and the various services running in user space through message passing. 6) Considering the memory layout of the following C program, the pointer x (in the red dashed box) is stored in A) uninitialized data section B) initialized data section C) stack D) heap