When should a line graph be used? A. When the independent variable is composed of categories and does not show a relationship.
B. When the independent variable is continuous and does not show a relationship to the dependent variable.
C. When there is no independent variable.
D. When the independent variable is continuous and shows a causal link to the dependent variable.

D. When the independent variable is continuous and shows a causal link to the dependent variable.

Explanation: Line graphs are usually very useful in visualizing relationships between variables (dependent and independent variable). Line graphs produce a very simple plot of these variables, however, by mere visualizing a line graph, one can tell if there exist a causal relationship between the measured variables. The independent variable when creating line graphs are real numerical values which should be continuous, aligning with the trend line produced by the graoh.

you need to give more information