Answer:
Sample Data set
Step-by-step explanation:
The group would consider their data to be a 'sample data set' as they primarily aim to generalize their discoveries to all freshman(number of pets in each household) which implies that the data will be used to represent a larger population. The '100 students' here is the part or subset of the population to represent it and since the results of the group will be used to estimate the characteristics/results of the population, the data set will be characterized as the sample set. Thus, option B is the correct answer.