Answer:
A. user mode
Step-by-step explanation:
A computer system is a machine that is run by a series of programs that connect the virtual parts (software) to the hardware or electronic parts. The kernel is a computer program that connects the software and hardware of a computer system.
The kernel-mode has several privileges like I/O, interrupts and traps, etc. This mode is tapped by root or administrators to utilize these privileges. Unlike the kernel mode, the user-mode does not have these functions, so a return from the trap instruction (kernel) reduces the privileges back to the user mode.