Which of the following pairs are universal gates

Options

A. NAND,NOT
B. NAND,AND
C. NOR,OR
D. NAND,NOR

Answer

To determine which pairs are universal gates, we need to understand what universal gates are and identify the pairs among the options provided.

### Step-by-Step Solution:

1. **Understand Universal Gates**:
- Universal gates are gates that can be used to create any other type of logic gate. The most common universal gates are NAND and NOR.

2. **Identify NAND Gate**:
- The NAND gate is a combination of an AND gate followed by a NOT gate. It can be used to construct any other logic gate, including AND, OR, and NOT.

3. **Identify NOR Gate**:
- The NOR gate is a combination of an OR gate followed by a NOT gate. Like the NAND gate, it can also be used to construct any other logic gate.

4. **Check the Options**:
- Given the options (A, B, C, D), we need to look for pairs that include either NAND or NOR gates.

5. **Conclusion**:
- Since both NAND and NOR gates are universal, any pair that includes either of these gates qualifies as a universal gate pair.

6. **Final Answer**:
- The pairs that are universal gates are NAND and NOR.