The Neighbours complained . . . . . . . . how loud our music was. A. of B. at C. on D. about

The correct answer is D. about.

The word “about” is used to introduce a topic or subject of discussion. In this case, the neighbors are complaining about the loudness of the music.

The other options are not as appropriate in this context. The word “of” is used to introduce a possessive noun or pronoun. The word “at” is used to indicate a location or position. The word “on” is used to indicate a surface or area.

Here are some examples of how the word “about” can be used in other sentences:

• I’m worried about my job.
• We talked about our plans for the weekend.
• I’m not sure about that.
• What are you talking about?