1. It is the key signature with one flat which is the B flat. *

Key of C Major
Key of D Major
Key of F Major
Key of G Major
2. It is the key signature with one sharp which is the F sharp. *

Key of C Major
Key of D Major
Key of F Major
Key of G Major
3. It is the key signature with no sharps or flats. *

Key of C Major
Key of D Major
Key of F Major
Key of G Major

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