What is the meaning of なのか in this sentence?


Any help in getting a better understanding of this sentence would be greatly
appreciated! Thank you!




In this case なのか is marking what is thought to be the cause of the following
clause (in Japanese).

> テナントで入っているショップのBGM **なのか** 、トランスが大音量で響いている。

Trance music was reverberating loudly, **perhaps from** the tenant shop's
background music.

