B. They did not survey employees in other offices around the country
Step-by-step explanation:
1. A random sample is when you randomly choose options from the whole list. In this case, they make it clear that there are other offices. They didn't give a chance to the rest of the offices to take a survey.
2. Surveying "all" the employees is not what a random sample is. A random sample is supposed to help make it more distributed among the people you survey. Making all of them take it in a cluster is not random.
3. The other choices don't make sense because they don't mention anything about them: nothing about the employees working 5 years, nothing about it being conducted electronically, and nothing about a time limit.
