Which notes are found in the Fr +6 chord in C major?

The Fr +6 chord, also known as the French augmented sixth chord, consists of specific intervals that define its characteristic sound. In the key of C major, the Fr +6 chord is built on the flattened sixth scale degree, which is A-flat. Therefore, from this root, the notes that make up the chord are:

1. The root, which is A-flat (the flattened sixth).

2. The third, which is C (the major third above A-flat).

3. The augmented fourth, which is D (the fourth degree, raised to give the augmented quality).

4. The augmented sixth, which is F (the sixth degree of the scale).

However, in the context of music theory, this chord is often spelled in a way that emphasizes the characteristic augmented sixth interval. In the key of C major, we would use the notes C, E, F, and A-sharp (or B-flat enharmonically, but in the context of augmented sixths, referring to A-sharp emphasizes the function of leading tones).

Thus, the correct answer indeed includes the notes C, E, F, and A-sharp, which form the Fr +6 chord in C major, leading naturally to the dominant chord, G major