Which of the following gates is called a universal gate?

Assertion: The logic gate $NOT$ can be built using a diode.
Reason: The output voltage and the input voltage of the diode have a $180^o$ phase difference.

In the logic circuit diagram, when all the four inputs, $A, B, C, D$ are 'one' the outputs $Y_1, Y_2, Y_3$ are respectively $(1, 1, 0)$. When the inputs $A$ and $C$ are changed to zero and $B$ and $D$ are still 'one',then the outputs $Y_1, Y_2, Y_3$ are respectively change to

The output of the given logic circuit is

In the adjacent circuit,$A$ and $B$ represent two inputs and $C$ represents the output. The circuit represents:

The truth table given below corresponds to which logic gate?

$A$	$B$	$Y$
$0$	$0$	$0$
$0$	$1$	$1$
$1$	$0$	$1$
$1$	$1$	$0$