Which logic operation yields an output of zero only when both inputs are zero?

Which logic operation yields an output of zero only when both inputs are zero?

• A. And
• B. Or
• C. Not
• D. Nand

Answer: (B)

The described behavior matches the OR operation. An OR gate outputs 0 only when both inputs are 0; if either input is 1, the output becomes 1. In boolean terms, A OR B = 0 only for A=0 and B=0; otherwise it equals 1. The other operations don’t fit: AND would give 0 whenever either input is 0 (not only when both are zero), NOT is a unary operation and doesn’t take two inputs, and NAND outputs 0 only when both inputs are 1.

The described behavior matches the OR operation. An OR gate outputs 0 only when both inputs are 0; if either input is 1, the output becomes 1. In boolean terms, A OR B = 0 only for A=0 and B=0; otherwise it equals 1. The other operations don’t fit: AND would give 0 whenever either input is 0 (not only when both are zero), NOT is a unary operation and doesn’t take two inputs, and NAND outputs 0 only when both inputs are 1.