Final answer:
The correlation with the strongest relationship is -0.8.
Step-by-step explanation:
The correlation coefficient measures the strength and direction of the relationship between two variables. In this case, we need to determine which correlation coefficient indicates the strongest relationship. The options are: A) -0.4, B) 0, C) -0.8, and D) 0.5. The correlation coefficient ranges from -1 to 1, with -1 indicating a perfect negative correlation, 0 indicating no correlation, and 1 indicating a perfect positive correlation. Therefore, the correlation with the strongest relationship is C) -0.8.