How many $NAND$ gates are required to construct an $AND$ gate?

$A$ person applies a sine wave and a square wave to an $AND$ gate as shown in figures $(i)$ and $(ii)$. Assuming that both the voltages are applied in phase, the person observes the output at $E$ and $F$ on $(i)$ and $(ii)$, respectively. [Assume a minimum voltage of $5 \ V$ is equivalent to logic $1$].

The combination of $NAND$ gates is shown in figures $(I)$ and $(II)$. For the given inputs,the outputs in both the combinations are respectively.

Given below are four logic gate symbols (figure). Those for $OR$,$NOR$ and $NAND$ are respectively:

The truth table for the given logic circuit is

In the circuit below,$A$ and $B$ represent two inputs and $C$ represents the output.