Which one of the following logic gates is called a Universal gate?

If the output of a $NAND$ gate is given as input to a $NOT$ gate, the resultant gate is

The output of an $OR$ gate is $1$.

If ${V}_{A}$ and ${V}_{B}$ are the input voltages (either $5\, V$ or $0\, V$) and ${V}_{0}$ is the output voltage,then the two gates represented in the following circuit $(A)$ and $(B)$ are:

For the logic circuit shown,the output waveform at $Y$ is

The truth table for the given circuit of four $NAND$ gates is: