Which of the following is the smallest distance between two notes?

To find the smallest distance between two notes, we need to determine the interval between them. In music, the smallest distance between two notes is called a half step, also known as a semitone. A half step is the distance between two adjacent keys on a piano, regardless of whether they are black or white keys.

To find the smallest distance, we can consider the musical alphabet, which consists of the letters A to G. When we move from one letter to the next without any sharps or flats in between, it is a half step or semitone.

For example:
- The distance between A and A# (A sharp) or Bb (B flat) is a half step.
- The distance between C and C# or Db is also a half step.

So, the smallest distance between two notes is always a half step, which is the shortest possible interval in music.