Identify the note at the 9th fret of the 4th (D) string.

The 4th string on a standard-tuned guitar is the D string. When identifying the note at the 9th fret of the D string, it's essential to understand how notes are laid out on the fretboard.

Starting from the open string, the note is D. Moving up one fret, you reach D# (or Eb), and one more fret brings you to E. Continuing this pattern, the notes at each fret of the D string are as follows:

• 1st fret: D#

• 2nd fret: E

• 3rd fret: F

• 4th fret: F#

• 5th fret: G

• 6th fret: G#

• 7th fret: A

• 8th fret: A#

• 9th fret: B

Therefore, if you count up to the 9th fret, you find that it indeed corresponds to the note B. This is why identifying the note as E at the 9th fret was not suitable since it falls on the 2nd fret, whereas the note at the 9th fret is B. Understanding the pattern of notes on the fretboard helps significantly in identifying notes accurately.