Which of the following statements is correct?

A. Changing the units of measurements of the explanatory or response variable does not change the value of the correlation.
B. A negative value for the correlation indicates that there is no relationship between the two variables.
C. The correlation has the same units (e.g., feet or minutes) as the explanatory variable.
D. Correlation between y and x has the same number but opposite sign as the correlation between x and y.