Question

1. what refers to the loudest tone that is produced?

fundamental tone
obstructive tone
alto tone
tenor tone

Explanation:

The fundamental tone (also called fundamental frequency) is the lowest - pitched and often the loudest tone produced by a vibrating object. Obstructive tone is not a standard term for the loudest tone. Alto and tenor tones refer to specific vocal ranges or pitches, not the loudest tone produced in general.

Answer:

A. fundamental tone