Which statement correctly describes a NAND gate's output for all inputs?

Which statement correctly describes a NAND gate's output for all inputs?

• A. Always outputs 0
• B. Outputs 1 when all inputs are 0
• C. Outputs 0 if all inputs are 1, and 1 otherwise
• D. Outputs 1 for any input

Answer: (C)

NAND is the inverse of AND: it outputs the opposite of what an AND gate would produce for the same inputs. So the output is 1 whenever not all inputs are 1, and it becomes 0 only when every input is 1. In other words, if any input is 0, the AND result is 0 and the NAND output is 1; only when all inputs are 1 does the AND result equal 1, making the NAND output 0. For example with two inputs: 00 → 1, 01 → 1, 10 → 1, 11 → 0. This matches the statement that describes the NAND output as 0 if all inputs are 1, and 1 otherwise. The other options fail because they either suggest the gate always outputs 0, or they describe a single case (like all zeros) without covering all input scenarios, or they claim 1 for every input, which is incorrect for the all-ones case.

NAND is the inverse of AND: it outputs the opposite of what an AND gate would produce for the same inputs. So the output is 1 whenever not all inputs are 1, and it becomes 0 only when every input is 1. In other words, if any input is 0, the AND result is 0 and the NAND output is 1; only when all inputs are 1 does the AND result equal 1, making the NAND output 0. For example with two inputs: 00 → 1, 01 → 1, 10 → 1, 11 → 0. This matches the statement that describes the NAND output as 0 if all inputs are 1, and 1 otherwise. The other options fail because they either suggest the gate always outputs 0, or they describe a single case (like all zeros) without covering all input scenarios, or they claim 1 for every input, which is incorrect for the all-ones case.