Take a look at this image: Grayed out notes after the treble clef on the first row of music notations. The second row shows ranges for bass notes, with numbers under each note, such as 8, 6 to 4, 6, and more.

Photo by Mezzofortist, distributed under a CC BY-SA 3.0 license.

What does this image likely demonstrate?

A.
the use of figured bass

B.
the use of a trill

C.
the use of grace notes

D.
the use of oratorio
(C is not the right answer)