The CEO of a company wants to determine whether taking the employees to a company retreat would boost their morale. He decides to survey a simple random sample of 50 of the 250 employees. Which of the following options would guarantee a simple random sample? asking the first 50 employees who come to work on Monday morning to take the survey telling the managers in each of the 5 departments to randomly select 10 people to take the survey giving each employee a unique number from 1 to 250 and randomly selecting 50 people to take the survey sending an email to all 250 employees asking them to complete the survey within the next couple of days