Answer:
A. This data set has two modes. Both 3 and 4 are the modes of the data set.
Explanation:
The mode is a statistical measure that represents the most frequently occurring value in a data set. In the given data set, 1 appears once, 2 appears once, 3 appears three times, 4 appears three times, 5 appears once, and 7 appears once. Since both 3 and 4 appear three times, the data set has two modes, which are 3 and 4. Therefore, the correct answer is A: "This data set has two modes. Both 3 and 4 are the modes of the data set." Option B is incorrect because the mode cannot be calculated by taking the average of the values that appear most frequently, and option C is incorrect because the data set does have modes.