Which of the sentences contain both an independent and a dependent clause?

A.
He was listening intently to the radio, and he didn't hear the doorbell.

B.
As she entered the auditorium, she tripped over a backpack that had been carelessly left in the doorway.

C.
Visiting the aquarium turned out to be quite an adventure; I enjoyed it thoroughly.

D.
We understand the environmental concerns of the farming community, but we are aware that business owners have another point of view.

D.

We understand the environmental concerns of the farming community, but we are aware that business owners have another point of view.

The sentence that contains both an independent and a dependent clause is:

D. We understand the environmental concerns of the farming community, but we are aware that business owners have another point of view.

To identify which sentences contain both an independent and a dependent clause, we need to understand the difference between these types of clauses.

An independent clause is a complete sentence that can stand alone and express a complete thought. It contains a subject and a predicate and does not rely on any other clause to make sense.

A dependent clause, on the other hand, is an incomplete sentence that cannot stand alone and does not express a complete thought. It relies on another clause to complete its meaning.

Let's analyze the given sentences:

A. "He was listening intently to the radio, and he didn't hear the doorbell."
This sentence contains two independent clauses separated by a coordinating conjunction ("and"). Both clauses can stand alone as complete sentences: "He was listening intently to the radio" and "he didn't hear the doorbell." Therefore, Sentence A contains both an independent and a dependent clause.

B. "As she entered the auditorium, she tripped over a backpack that had been carelessly left in the doorway."
This sentence contains one independent clause ("she tripped over a backpack that had been carelessly left in the doorway") and one dependent clause ("As she entered the auditorium"). The dependent clause relies on the independent clause to complete its meaning. Thus, Sentence B contains both an independent and a dependent clause.

C. "Visiting the aquarium turned out to be quite an adventure; I enjoyed it thoroughly."
This sentence comprises two independent clauses separated by a semicolon. Each clause can stand alone as a complete sentence: "Visiting the aquarium turned out to be quite an adventure," and "I enjoyed it thoroughly." The sentence does not contain a dependent clause, so Sentence C does not meet the criteria.

D. "We understand the environmental concerns of the farming community, but we are aware that business owners have another point of view."
This sentence contains two independent clauses separated by a coordinating conjunction ("but"). Both clauses can stand alone as complete sentences: "We understand the environmental concerns of the farming community" and "we are aware that business owners have another point of view." There is no dependent clause here, so Sentence D does not meet the criteria.

In conclusion, both Sentences A and B contain both an independent and a dependent clause.