Can you only pick one choice?
Well since you don't have a clef, it must not be answer A. Those notes are quarter notes so I would say it talks about the duration of the note.
But waaaait, why are there two? It could be C haha.
http://prntscr.com/8p11qu this is the right one i put the worng one
Whoops idk how that last comment got reposted, but anyways, Each of those indicate a specific note length. The first one is a whole note, the second one is a half note, the third is a quarter note, the fifth is a eighth, and the last is a sixteenth.
I guess it's probably D. o.o