The correct answer is (a) C.P.U.
The CPU is the brain of the computer. It is responsible for carrying out the instructions that are given to it by the user. The CPU is made up of millions of tiny transistors that work together to perform calculations.
The keyboard is used to enter data into the computer. The data can be text, numbers, or commands. The keyboard is connected to the CPU by a cable.
The disc is used to store data. The data can be programs, files, or documents. The disc is connected to the CPU by a cable.
The printer is used to print data from the computer. The data can be text, numbers, or images. The printer is connected to the CPU by a cable.
The CPU is the most important part of a computer because it is responsible for carrying out the instructions that are given to it by the user. The other parts of the computer are important, but they cannot function without the CPU.