In which of the following gates, the output is 1, if and only if at least one input is 1?
Answer: C
In OR gate we need atleast one bit to be equal to 1 to generate the output as 1 because OR means any of the condition out of two is equal to 1 which means if atleast one input is 1 then it shows output as 1 . Number of 1's in input may be more than one but the output will always be 1 in OR gate. So the answer is 'C'.