This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to protect a basement from flooding
Get a propane or natural gas generator.
Do not waste your time buying a gasoline powered generator. You will have to be at home at the time of the power outage to start it.

Select from:
A). This generator should be at least 10 ft (4.6 m) or less. One gallon (3.7 l) of propane, combined with a common gas, is likely to have a significant footprint on your basement.;
B). Electricity goes directly into your basement and should be replaced every 10 days for at least 5 years. You should also make sure the generator is rated with the appropriate efficiency and appropriate waste content.;
C). Above all else, you want to make sure that you water the basement well in case of a fire. Check the system often to make sure that there are no electrical issues.;
D). You'll also have to keep returning to your home to add gasoline. There is a wide variety of propane or natural gas generators that run automatically when your power goes out.;
The answer is:
D).