The output of a logic gate is low when any one of the inputs is high. Which gate does this statement describe?

In the given circuit,the output $Y$ becomes zero for the inputs

The combination of $NAND$ gates shown in the figure is equivalent to:

Which logic gate is represented by the following truth table?

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

In the Boolean algebra,the expression $\left( {\overline {\bar A \cdot \bar B} } \right) \cdot A$ is equal to:

$A$ combination of logic gates is as shown in the figure. $P$,$Q$,$R$,and $S$ are the inputs and $X$,$Y$,and $Z$ are outputs. When inputs $P$ and $R$ are 'low' $(0)$ and $Q$ and $S$ are 'high' $(1)$,the outputs $X$,$Y$,and $Z$ are respectively: