The two combinations of $NAND$ gates shown in the figures are equivalent to:

In a digital circuit for three input signals $(A, B, \text{ and } C)$, the final output $(Y)$ should be such that for inputs:
| $A$ | $B$ | $C$ |
|---|---|---|
| $0$ | $0$ | $0$ |
| $0$ | $0$ | $1$ |
| $0$ | $1$ | $0$ |
the output $(Y)$ should be $0$, and for all other cases, it should be $1$. Which of the following digital circuits will give such output?

Write the function of $AND$ gate.

Which of the following gates is called a universal gate?

The output of the circuit is low (zero) for: $(A) \ X = 0, Y = 0$,$(B) \ X = 0, Y = 1$,$(C) \ X = 1, Y = 0$,$(D) \ X = 1, Y = 1$. Choose the correct answer from the options given below:

The given logic circuit is equivalent to which of the following gates?