In computer architecture, which combination correctly lists the main types of buses used in a typical microprocessor based system?

Introduction / Context:
In a microprocessor based system, the processor must communicate with memory and input output devices using shared electrical connections called buses. These buses carry different kinds of information such as data, addresses and control signals. Understanding the standard classification of system buses helps students visualise how components interact and how instructions are fetched and executed.

Given Data / Assumptions:

We are considering a typical microprocessor system with a central processing unit, memory and I O devices.
Buses are groups of parallel wires or traces that carry related signals between components.
Different buses serve different logical roles, even if they may share physical wiring in some designs.
The question asks for the combination that correctly lists the main bus types in most textbook microprocessor diagrams.

Concept / Approach:
The data bus carries binary data values between the CPU, memory and I O devices. It is usually bidirectional, because data may flow to or from the processor. The address bus carries address information from the CPU to memory and devices, indicating which location is being read or written. It is usually unidirectional out of the CPU. The control bus carries control signals such as read, write, clock and interrupt lines that coordinate the timing and direction of bus transactions. These three categories appear in nearly all introductory block diagrams and collectively describe the main types of system buses.

Step-by-Step Solution:
Step 1: Identify that the data bus must exist to transfer actual instruction bytes and data values between memory, the CPU and peripherals. Step 2: Recognise that the address bus is needed so that the CPU can specify which memory location or device register it wants to access. Step 3: Understand that control signals such as read enable, write enable, clock and interrupt requests must also be communicated, which is the role of the control bus. Step 4: Evaluate the options and select the one that lists data bus, address bus and control bus, which matches the standard classification.

Verification / Alternative check:
Open any introductory textbook on computer organization and examine the block diagram of a simple microprocessor system. You will usually see three labeled groups of lines connecting the CPU and memory: address bus, data bus and control bus. Sometimes the buses are drawn separately; sometimes a shared system bus is shown with signal types grouped logically. This consistent appearance across references confirms that these three types are the primary buses in typical systems.

Why Other Options Are Wrong:
Video, audio and power buses are not standard categories in basic microprocessor diagrams. Video and audio signals are handled by specific subsystems, and power lines are not classified as logical buses in the same sense.
The idea of only a single undifferentiated bidirectional bus oversimplifies system design. Even when physical lines are shared, signals are conceptualised as data, address and control for clarity and design purposes.
Printer, keyboard and hard disk buses refer to specific external interfaces rather than fundamental bus types used inside the core architecture.

Common Pitfalls:
Learners sometimes confuse logical bus types with brand specific interfaces such as USB, SATA or PCI Express. Those are standards that define how devices share lines, but underlying concepts of data, address and control signals still apply. Another pitfall is to assume that modern high speed serial buses eliminate the need to reason about these categories, even though hardware designers still think in terms of what information is being transmitted.

Final Answer:
The main bus types in a typical microprocessor system are the data bus, address bus and control bus.