Which type of logic is formed by two or more normally closed switches in parallel?

The correct answer is NOR logic. When two or more normally closed switches are connected in parallel, the configuration represents a logical operation that is similar to the NOR gate function in digital logic.

In a NOR configuration, the output will only be low (or false) when all switch inputs are high (or open). If any of the normally closed switches are closed (which corresponds to a high input), the circuit will complete, leading to a low output. Thus, this setup fulfills the criteria for NOR logic, where the output is only true when all inputs are false.

In contrast, NAND logic would require at least one input to be true for the output to be false, which does not apply in this scenario, as normally closed switches will maintain a closed connection unless overridden. Similarly, AND logic would require all switches to be closed for an active output, which is not the same function as NOR. Finally, XOR logic deals with exclusivity, where the output only activates when there is an odd number of true inputs, but this logic doesn't apply to a configuration of normally closed switches in parallel. Hence, the logic formed by the described switch arrangement is accurately characterized as NOR logic.