Question

The given truth table is for:

Input	Input	Output
A	B	Y
0	0	1
0	1	1
1	0	1
1	1	0

(A) AND gate
(B) OR gate
(C) NAND gate
(D) NOR gate

Answer 1

Hint
The solution for this question can be easily found by writing down the truth tables of all the four logic gates. Comparing each of them with the given truth table would give the correct answer.
Formula used: The logic equations for each of the gates are:
AND gate: $Y = A \bullet B$
OR gate: $Y = A + B$
NAND gate: $Y = \overline {A \bullet B}$
NOR gate: $Y = \overline {A + B}$ while $A$ and $B$ are the two logical inputs, $Y$ is the output, $\bullet$ represents the logical multiplication operator and $+$ represents the logical addition operator.

Complete step by step answer
As we mentioned above, we have to find out the truth tables for each of the gates provided in the options. So, for the AND gate, the output is ‘high’ represented as $1$ only when both the outputs are ‘high’, and otherwise the output is ‘low’ represented as $0$ . The truth table for the AND gate is:

Input	Input	Output
$A$	$B$	$Y = A \bullet B$
0	0	0
0	1	0
1	0	0
1	1	1

Similarly, for an OR gate, the output is high when at least one of the inputs is high. The output is low only if both the inputs are low. The truth table for the OR gate is as follows:

Input	Input	Output
$A$	$B$	$Y = A + B$
0	0	0
0	1	1
1	0	1
1	1	1

Now, the NAND gate is the complement of an AND gate. That is, if both the inputs are high, then the output of a NAND gate is low, and whenever there is a low input, the output is high. This can be illustrated in the truth table as:

Input	Input	Output
$A$	$B$	$Y = \overline {A \bullet B}$
0	0	1
0	1	1
1	0	1
1	1	0

Similar to the case of NAND gate, NOR gate is the complement of an OR gate. So, in this case, the output is high only when all the inputs are low, and if there is at least one high input, then the output of the NOR gate is low. The truth table is follows:

Input	Input	Output
$A$	$B$	$Y = \overline {A + B}$
0	0	1
0	1	0
1	0	0
1	1	0

So, on comparing the truth tables of all the four gates given in the options, the truth table of NAND gate is equivalent to the truth table given in the question.
Therefore, the correct answer is option (C).

Note
There is one more primary logic gate which is not discussed in this question. That is the NOT gate. The NOT gate works as an inverter, that means, whatever is there in the input; its negation will be the output. When the input is low, then the output will be high and vice-versa. These logic gates play a great role in the electronics industry and logic gates are the very basic building blocks of almost all of the electronic devices.