The answer is b, 16th notes are the shortest and quickest out of the options
<em>a</em><em>n</em><em>s</em><em>w</em><em>e</em><em>r</em><em> </em><em>:</em>
<em>v</em><em>i</em><em>o</em><em>l</em><em>i</em><em>n</em><em> </em><em>c</em><em>o</em><em>n</em><em>c</em><em>e</em><em>r</em><em>t</em><em>o</em><em>.</em>
It's pronounced "ensemble" by the way. And, one way that a pianist would have a role would be by being in the background as an example and playing his part. He's going to play what he needs to play. The question does seem a little to vague, but truly, I would say simply, that the person who is playing it, just plays his part as they all make music sound good.
