The most credible nonhuman source about a new and promising treatment for sleep apnea is option B) “a study comparing patients who have been treated with the new treatment to patients who have been treated with the old treatments”. This option compares the results of people using the new treatment and people who didn't use the new treatment. By doing this, we are showing irrefutable data based on an objective analysis of the results obtained.
Option A is incorrect as it is only showing medical records of people suffering from apnea but does not mention the new treatment.
Option C is also incorrect since it tells the story of a particular case that did not use the new treatment and how it affected her life.
And option D mentions only a survey taken from people suffering apnea and no evidence of the results of new treatment is given.