A multitasking operating system can have several processes running at the same time. What are the components within the processes that are shown in the graphic that follows?

A.
Threads

B.
Registers

C.
Address buses

D.
Process tables

Explanation:
A: A process is a program in memory. More precisely, a process is the program’s instructions and all the resources assigned to the process by the operating system.
It is just easier to group all of these instructions and resources together and control them as one entity, which is a process. When a process needs to send something to
the CPU for processing, it generates a thread. A thread is made up of an individual instruction set and the data that must be worked on by the CPU. Most applications
have several different functions. Word processors can open files, save files, open other programs (such as an e-mail client), and print documents. Each one of these
functions requires a thread (instruction set) to be dynamically generated. So, for example, if Tom chooses to print his document, the word processor process generates
a thread that contains the instructions of how this document should be printed (font, colors, text, margins, and so on). If he chooses to send a document via e-mail
through this program, another thread is created that tells the e-mail client to open and what file needs to be sent. Threads are dynamically created and destroyed as
needed. Once Tom is done printing his document, the thread that was generated for this functionality is destroyed.
B is incorrect because a register is a temporary storage location. Processing chips within the CPU cover only a couple of square inches but contain over millions of
transistors. All operations within the CPU are performed by electrical signals at different voltages in different combinations, and each transistor holds this voltage, which
represents 0s and 1s to the computer. The CPU contains registers that point to memory locations that contain the next instructions to be executed and that enable the
CPU to keep status information of the data that needs to be processed. While a register can hold the instructions that make up the thread before it is fed into the CPU, it
is not a component of the process themselves.
C is incorrect because an address bus is a hardwired connection to RAM chips and the individual input/output (I/O) devices in a computer system. In a computer,
memory addresses of the instructions and data to be processed are held in registers until needed by the CPU. The CPU is connected to the address bus. Memory is cut
up into sections that have individual addresses associated with them. I/O devices (CD-ROM, USB device, hard drive, and so on) are also allocated specific unique
addresses. If the CPU needs to access some data, either from memory or from an I/O device, it sends down the address of where the needed data is located. The
circuitry associated with the memory or I/O device recognizes the address the CPU sent down the address bus and instructs the memory or device to read the
requested data and put it on the data bus. So the address bus is used by the CPU to indicate the location of the instructions to be processed, and the memory or I/O
device responds by sending the data that resides at that memory location through the data bus.
D is incorrect because a process table is a way for an operation system to keep track of processes that are running. An operating system is responsible for creating
new processes, assigning them resources, synchronizing their communication, and making sure nothing insecure is taking place. The operating system keeps a process
table, which has one entry per process. The table contains each individual process’s state, stack pointer, memory allocation, program counter, and status of open files in
use. The reason the operating system documents all of this status information is that the CPU needs all of it loaded into its registers when it needs to interact with, for
example, process 1. When process 1’s CPU time slice is over, all of the current status information on process 1 is stored in the process table so that when its time slice
is open again, all of this status information can be put back into the CPU registers. So, when it is process 2’s time with the CPU, its status information is transferred from
the process table to the CPU registers; it is transferred back again when the time slice is over.