The correct answer is option 1: "because they reflect the sound to the audience."

Ceilings in concert halls are typically curved to improve the acoustics of the space. When sound is produced on the stage or in front of the audience, the curved ceiling helps to reflect the sound waves towards the audience. This enhances the audio experience and allows the sound to reach everyone in the hall more evenly.

Option 2, which suggests that curved ceilings absorb noise, is incorrect. Absorbing noise is generally not the main purpose of a concert hall ceiling. While some materials used in the construction of the ceiling may have sound-absorbing qualities, the primary goal is to maximize sound reflection and distribution to enhance the listener`s experience.

Option 3 suggests that curved ceilings are designed for better aeration in the hall, but the primary purpose of a concert hall ceiling is to improve the acoustics. Aeration and ventilation are typically addressed through other means, such as HVAC systems.

Option 4, stating that a curved ceiling prevents outside sounds from passing through, is not accurate. The shape of the ceiling does not directly affect the transmission of sound from the outside. Other factors like insulation and the construction of the walls and windows play a more significant role in preventing outside