What type of phonation is measured in terms of intensity during refresher sessions?

The correct choice is focused on the duration and intensity of sustained phonation of "ah" because this type of phonation is specifically structured to assess and enhance a person's vocal strength and control. Sustained phonation exercises, particularly the "ah" sound, allow for a clear measurement of both the duration of the sound being held and the intensity, or loudness, maintained throughout the phonation.

This method is often used in speech therapy and vocal training because it provides quantitative data on a person's ability to produce sound consistently, which is crucial for various speech functions, including clarity and volume in speaking situations. By focusing on the intensity during refresher sessions, individuals can work towards improving their vocal robustness and overall communication efficacy.

The other options do not focus as directly on these specific measurements or do not provide the systematic approach needed for assessing phonation intensity during training sessions. For example, sustained "ee" sound may not assess intensity in the same way, and rapid speech exercises focus more on fluency than on phonation control. Conversational phonation lacks the structured intensity assessment that sustained phonation offers.