F major and its relative harmonic minor, D minor, have only b flat.
It's not too bad, there's only three flats in the key signature; Bb, Eb, and Ab.
Bb is not necessarily an easier key, however it only has 2 flats in its key signature, whereas Ab has 4. So if you're composing for an instrument, the key of Ab would be better.
The key signature is E flat major, which is also, C minor, the relative minor of E flat major. You can find out what flat key signature you're in by finding the second to last flat (in this case E flat). It is the major version of that key signature!
A sharp key signature is one that contains sharps.
Bb or F
There is no key signature that has Bb and C#.
The scale that has two flats in its key signature is the key of Bb major.
The scale with 2 flats in its key signature is the key of Bb major.
The key signature will consist of two flats: Bb, and Eb.
Bb and Eb
It's not too bad, there's only three flats in the key signature; Bb, Eb, and Ab.
One flat, Bb.
Bb, Eb and Ab
The key signature for the C Dorian mode is two flats: Bb and Eb.
The key signature of a musical scale with two flats is Bb major.
Bb is not necessarily an easier key, however it only has 2 flats in its key signature, whereas Ab has 4. So if you're composing for an instrument, the key of Ab would be better.
The key with three flats (Bb, Eb, Ab) is the key of Eb.