Engine 2014: Electricity

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

Tip: press A-D to answer