With reference to timbre—the rhythmic layer is being provided by which instrument?

What is the term for a sign, in a system of writing, that denotes a particular sound?

A) ?syllabogram B) ?kiva C) ?logogram D) ?formoglyph

Arguably the most essential ingredient in jazz is:

A. rhythm (syncopation). B. improvisation. C. the front-line instruments. D. the “standards.”