C sharp
Any note which has the word 'sharp' in it is always a semitone above the given note.
Tone and semitone are two words to describe differences in pitch between two notes. A semitone is the difference between F and F#, that is, only a bit. A tone is the difference between F and G, twice as much as a semitone.
Both of them are diatonic scales. Major scale is written as per key signature. Harmonic minor scales have a raised 7th. The semitone leaps in these scales are different.
All harmonic minor scales have the pattern of tone-semitone-tone-tone-semitone-tone-tone (raised 7th)-semitone. Therefore, D harmonic minor has the notes of D, E, F, G, A, B flat, C# (raised 7th), D.
F flat.
E Double Flat
It is diatonic. Di means two, so you can think of it as two tones. A chromatic semitone would be from D to D#, or Eb to E. The difference is that Chromatic semitones use the same letter name twice, while diatonic semitones do not.
B
c flat. the semitone above b flat is b, with is equal to c flat. So the diatonic semitone is c flat because it has to be a different note name.
G flat
C sharp
A C flat
B Double Flat
Raised a semitone, it becomes F-sharp.
From e natural to f natural is a semitone. To make this a tone, raise the f to f sharp, or alternatively lower the e to e flat.
A diatonic semitone is usually represented by the adjacent letter names. The next higher letter pitch to C is D. The answer is D (natural).