Solution

The correct answer is A - IV, B - I, C - II, D - III

Key Points

• Half Adder:
  • A Half Adder is a combinational logic circuit that performs the addition of two bits. It produces a sum and a carry value as output. Hence, it is a 2-bit addition circuit. So, A matches with IV.
• Decoder:
  • A Decoder is a combinational circuit that converts binary information from n input lines to a maximum of 2ⁿ unique output lines. It is used to decode encoded data. So, B matches with I.
• Register:
  • A Register is a small amount of storage available as part of a CPU. It is used to store data temporarily while programs are running. So, C matches with II.
• Main Memory:
  • Main Memory, also known as RAM (Random Access Memory), is used to store the program that is currently being executed and the data that is being processed by the CPU. So, D matches with III.

Therefore, the correct option is A - IV, B - I, C - II, D - III. So, the correct option is 3).