A half step, also known as a semitone, is the smallest musical interval commonly used in Western music.
Let's evaluate each pair you mentioned:
- G to A-flat: This is a half step. G and A-flat are adjacent notes on the piano keyboard.
- E to F-sharp: This is also a half step. E and F-sharp are next to each other.
- C to B-flat: This is a whole step, comprising two half steps (there's a B natural between C and B-flat).
Since both G to A-flat and E to F-sharp are half steps, the correct answer from your choices is "all of the above" except for C to B-flat, which is a whole step. Therefore, the only correct pairs that represent a half step are G to A-flat and E to F-sharp. However, if the question is about specifically identifying the half steps without excluding any options, then "all of the above" would be misleading as an answer due to the presence of C to B-flat.
So, the specific half steps in your original list are G to A-flat and E to F-sharp.