Which element of musical notation does this image represent?

A.
bass clef
B.
beam
C.
grand staff
D.
treble clef

A.  bass clef

D.  treble clef

Explanation:

As per the image, it represents two kinds of clefs, the treble clef and the bass clef. Where the clef is the symbol which is used to represent the pitch of the musical note, a bass clef is a symbol that denotes the start of the second line of the musical note and the treble clef denotes the line above the musical note.

The treble is also known as the G clef whereas the the bass is known as the F clef.

the string with the finger instead of using the bow