The correct answer is B. the hollow box within a violin. This large, flat piece of wood found in a piano produces the sound when the piano is played, the same way the hollow box produces the sound coming from a violin. The two items have the same purpose, which is to provide the instrument with sound.
When it is has a probability value of 0.1587, it means
that 15.87% of the total sample is below z = -1 or there is a chance that the
selected sample has a 15.87% chance of being below z = -1. Actually all the
choices are telling the same thing in different way.
