Final answer:
The mode of the given data set is 4.
Step-by-step explanation:
The modes of a data set are the values that appear most frequently. To find the modes of the given data set: 8, 4, 8, 5, 5, 5, 7, 4, 4, 5, 4. First, we can organize the data in numerical order: 4, 4, 4, 4, 5, 5, 5, 7, 8, 8. From this list, we can see that the mode is 4, as it appears most frequently (four times). Therefore, the correct answer is B) 4.