Answer:
The university study.
Step-by-step explanation:
In this example, a blog about solar energy would probably be informative, but since it is not an academic source, it could be written by anyone and the information would have to be taken with a grain of salt.
A company website would not be a good source because the information on the website would be furthering the interests of the business.
A university, on the other hand, would have access to the latest scientific, proofread papers on solar energy research.