During a context switch in direct execution, what specific actions does the operating system typically perform to maintain process isolation?

It only saves the state of the CPU registers for the currently running process.

It saves and restores the state of the CPU registers and updates the program counter for the process to be executed next.

It updates the memory access rights for the next process to ensure that it cannot access the memory of the previous process.

It clears the memory unit completely to prepare for the next process.