Which logic gate represents the function A + B?

The function A + B is represented by the OR gate. In digital logic, the expression A + B indicates that the output will be high (1) if at least one of the inputs A or B is high (1). The OR gate effectively performs this operation, producing a true output for all combinations of A and B, except when both inputs are false (0).

For example, if A is 0 and B is 1, the output of the OR gate will be 1. Similarly, if A is 1 and B is 0, the output remains 1. Only when both A and B are 0 will the output be 0. This behavior aligns perfectly with how the OR operation is defined, making it the correct choice for the given function.

In contrast, the other gates do not represent the function A + B accurately. The NAND gate produces the opposite of an AND operation, the AND gate requires both inputs to be true for a true output, and the XOR gate outputs true only when the inputs are different. Therefore, none of these gates fulfill the requirements of the A + B function as successfully as the OR gate does.