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

• A

  $\mathrm{OR}$
• B

  NAND
• Correct answer
  C

  AND
• D

  NOR.

Solution

Truth table $$ \begin{array}{rrrrr} A & B & A^{\prime} & B^{\prime} & Y \\ 0 & 0 & 1 & 1 & 0 \\ 0 & 1 & 1 & 0 & 0 \\ 1 & 0 & 0 & 1 & 0 \\ 1 & 1 & 0 & 0 & 1 \end{array} $$
$$ \text { Output of this is same as that of AND gate. } $$

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