The question asks for the truth table of a circuit made of four NAND gates, but the required figure/circuit diagram is missing from the prompt.

Without the interconnection of the four NAND gates, the truth table cannot be uniquely determined, because different arrangements of four NAND gates can implement very different logic functions (for example: AND, OR, XOR, XNOR, latch-like structures, etc.).

Step-by-step reasoning

1. A NAND gate gives output $Y = \overline{AB}$

2. To find the truth table of a system of four NAND gates, we must know:

   • how many inputs the circuit has,
   • which outputs feed into which inputs,
   • whether any NAND gate is used as a NOT gate by tying its inputs together.

3. Since the figure is not provided, none of the options A/B/C/D can be verified from the information available.

4. Therefore, the truth table cannot be solved uniquely from the given text alone.

Comparison with stored answer

The stored correct answer is A, but because the circuit diagram is absent, I cannot derive or verify that result mathematically.

So I do not agree with the stored answer based on the currently provided information—not because A is necessarily wrong, but because the question is incomplete.