Based on the content of this passage, what question could you ask yourself to check your comprehension of this passage?

Although some of these bikes might seem odd to you, or even impractical, they do have some valid and important purposes. For starters, investigations into human-generated kinetic energy might contribute to real solutions to the creeping energy crisis by providing a clean and renewable source of energy. Such solutions will have the added bonus of making users more fit, something flipping your light switch or unplugging your toaster can?t do. Secondly, machines like this have the potential to do a lot of good in developing countries that don?t always have easy access to appliances, affordable machinery, or cheap electricity. In fact, several organizations exist to help get bike-based technology into the hands of communities working to become financially stronger.
a.
How could these bikes contribute to energy use?
c.
both of these
b.
Why do people ride bikes to work in big cities?
d.
neither of these

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