Choose the logic gate that corresponds to the truth table

$\begin{array}{ccccc}\mathrm{A}& 0& 0& 1& 1\\ \mathrm{B}& 0& 1& 0& 1\\ \mathrm{X}& 0& 1& 1& 1\end{array}$

 

In the following circuit, what are $P$ and $Q?$

Given below are four logic gate symbols. Those for $\mathrm{OR}$, $\mathrm{NOR}$ and $\mathrm{NAND}$ are, respectively.

The Boolean expression for the output $Y$ of the logic operation shown is-

If $a\text{,} b\text{,} c\text{,} d$ are inputs to a gate and $x$ is its output, then, as per the following time graph, the gate is,

Which type of gate the following truth table represents? 

The truth table for the following circuit is

The figure shows a logic circuit with two inputs $A$ and $B$ and the output $C$. The voltage waveforms across $A$, $B$ and $C$ are as given. The logic circuit gate is