what is one reason certain key signatures are used? to confuse performers, to match with other pieces of the time period, to satisfy a client, or to fit the instruments that will be playing the piece

Answer 1

One reason certain key signatures are used is to fit the instruments that will be playing the piece. Different instruments have different natural ranges and tonalities, and certain key signatures are better suited for specific instruments. Choosing an appropriate key signature ensures that the music lies comfortably within the playable range of the instruments involved.