Q1: If a signal passing through a gate is inhibited by sending a LOW into one of the inputs, and the output is HIGH, the gate is a(n):

ANS:B - NAND

Check the answer using two inputs it also gives the same answer that I explain using three inputs.

Considering the truth table of NAND gate.
A B OUTPUT
0 0 1
0 1 1
1 0 1
1 1 0 = here we get the output HIGH when the two inputs are LOW.

Considering the truth table for OR gate.
A B OUTPUT
0 0 0
0 1 1
1 0 1
1 1 1 = here the output is HIGH when the two inputs are HIGH.

BUT question said first input must be LOW when the output is HIGH. So we can't get OR gate as the answer.