Which one of the following is the Boolean expression for $NOR$ gate?

Boolean algebra is essentially based on

For the given combination of logic gates, if the logic states of inputs $A, B, C$ are as follows: $A = B = C = 0$ and $A = B = 1, C = 0$, then the logic states of output $D$ are:

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

The circuit diagram shown here corresponds to which logic gate?

The inputs to the digital circuit are as shown below. The output $Y$ is