Explanation:

The main circuit board of a computer, which integrates and connects all essential components like the CPU, memory, and expansion slots, is universally known as the "Motherboard." It acts as the central hub, providing electrical connections and communication pathways for the entire system. Option (a) "Father board" is not a recognized term in computer architecture. Option (c) "Keyboard" is an input device used for typing, not the main circuit board. Since (a) and (c) are incorrect, option (d) "All of these" is also incorrect. Option (e) is incorrect as (b) is the accurate and widely accepted term for the main circuit board.