Engine: Electricity

1. A Both "Input 1" and "Input 2" must be closed OR both "Input 3" and "Input 4" must be closed.
2. B Both "Input 1 and "Input 2" must be closed AND either "Input 3" or "Input 4" must be closed.
3. C Either "Input 1" or "Input 2" must be closed OR both "Input 3" and "Input 4" must be closed.
4. D Either "Input 1" or "Input 2" must be closed AND either "Input 3" or "Input 4" must be closed.

Tip: press A-D to answer