If you strike percussion instruments with yarn wrapped mallets it produces a A louder sound B brighter sound C softer sound D shorter sound?

It usually gives a deeper, longer sound, compared to a hard mallet that produces a sharp and short sound. It also depends on the density of yarn and how tightly is is wrapped around the core, and also what the core is made of. A tightly wrapped hard yarn mallet will be more staccato then a loosely wrapped soft yarn mallet.