Respuesta :
Answer:
The results could be flawed due to non-response of patients.
Step-by-step explanation:
A doctor's office mails a survey to each of its patients. The results of the survey are based off of the total number of patients. The office is mailing the patients. It is very likely that patients do not read out the survey mail. So, they cannot respond to the survey or a very few patients will respond back. So, option 4th is the correct. The results could be flawed due to non-response of patients.