Refer to the Department of Energy's "Guide to Renewable Energy." How does the article make a connection between solar and wind systems?

A. Solar and wind systems can be cost-effective, but both depend on the availability of their energy sources to work.

B. Solar and wind systems are both grid-connected, so users can sell back their excess energy, making their costs more feasible.

C. Buyers need to check zoning laws and building codes when considering wind systems, while those wanting solar systems do not need to.

D. Homeowners should keep the space requirements in mind for solar panels, but wind turbine towers have no such restrictions.