Final answer:
The mode would be the most effective measure of central tendency to emphasize how small the data values are.
Step-by-step explanation:
The measure of central tendency that would be most effective in emphasizing how small the data values are in the set {32, 21, 58, 21, 43} is the mode.
The mode is the value that appears most frequently in a data set. In this case, the value 21 appears twice, which is more frequently than any other value in the set. By identifying the mode, we can see that the most common value in the data set is small relative to the other values.