Which of the following sentences is a compound sentence?

Someone smelled smoke in the hallway.

The windows were closed and covered with grime.

Smoke and flames were everywhere.

The fire alarm sounded, and two engines raced to the scene.

Respuesta :

the laat one is the correct answer
The fire alarm sounded, and two engines raced to the scene. This is the compound sentence because if you split the sentence into two at the "and", two complete sentences are formed. That is also why a comma is after this "and" because it connects two complete sentences.