Correct Response: A. A flame-test protocol gives results that are qualitative in nature (e.g., the presence of sodium in Group 1 gives a yellow flame color). Qualitative results are conveyed with tables. All other options require numerical data (which is not obtained in this experiment). B is incorrect because a histogram requires a numerical value for frequency. C is incorrect because scatter plots are used to show the relationship between two numerical sets of data (e.g., a graph of students’ heights versus weights). D is incorrect because line graphs are used to show the numerical relationship between two sets of data.