Based on the given sentence above, I can say that it is a compound sentence. What makes this sentence compound is that, it consists of two independent clauses and are connected by a coordinating conjunction "so". Therefore, the answer for this would be the last option: two independent clauses.
A. It does not summarize the main points.
The mood is unsettling and suspenseful. The words "unfamiliar, concerned, unusually, and heavy" help set the mood to this.
Mis function is the answer to your question
