First Federal Financed the Purchase of O's Home and Recorded

First Federal financed the purchase of O's home and recorded a mortgage on September 12, 2020. O decided to build a swimming pool in the backyard. Suppose that First Interstate loaned O money for the purchase of a solar water heating system from The Solar Company. O purchased the system on February 1, 2021. Solar Experts installed the system on February 9, 2021. First Interstate filed a financing statement on February 8, 2021. Who has priority in the solar system?

A) First Federal
B) First Interstate
C) The Solar Company
D) Solar Experts