Computer Architecture:
Computer architecture refers to the design and organization of a computer system, including its components and how they interact. It defines the structure, behavior, and functionality of a computer system and determines how the hardware and software components work together to perform tasks.

Types of Computer Architecture:
There are different types of computer architecture, each with its own characteristics and design principles. The options provided in the question are all types of computer architecture.

a) Microarchitecture:
Microarchitecture, also known as computer organization, deals with the internal structure and design of a computer system. It focuses on implementing the architecture's specifications and includes the design of the CPU, memory, and other components. Microarchitecture defines the way instructions are executed and data is processed within the system.

b) Harvard Architecture:
Harvard Architecture is a computer architecture that separates the instruction and data memory. It has separate buses for instruction and data, allowing simultaneous access to both. This architecture is commonly found in embedded systems and microcontrollers.

c) Von-Neumann Architecture:
Von-Neumann Architecture is a computer architecture that uses a single bus to connect the CPU, memory, and other components. It stores both instructions and data in the same memory, and the CPU fetches, decodes, and executes instructions sequentially. This architecture is widely used in modern computers.

d) All of the mentioned:
The correct answer, option 'D', states that all the mentioned options (Microarchitecture, Harvard Architecture, and Von-Neumann Architecture) are types of computer architecture. This is true as each option represents a different approach to organizing and designing a computer system.

In summary, computer architecture encompasses different design principles and structures. Microarchitecture focuses on the internal design, Harvard Architecture separates instruction and data memory, and Von-Neumann Architecture uses a single memory for both instructions and data. All three options mentioned in the question are types of computer architecture.