Which logic gate is represented by the following combination of logic gates?

• A

  OR
• B

  NOR
• Correct answer
  C

  AND
• D

  NAND

Solution

Output of gate-1, $Y_1=\bar{A}$ Output of gate-2, $Y_2=\bar{B}$ Output of gate-3, $\begin{aligned} Y=\overline{Y_1+Y_2} & =\overline{\bar{A}+\bar{B}} \\ & =\overline{\bar{A}} \overline{\bar{B}} \\ & =A B \end{aligned}$ which is the output of AND gate.

Hence, the correct answer is option: 'C'.