Answer as requested. Which of the following pairs of variables is likely to have no correlation?

A. The unemployment rate and the number of home foreclosures.
B.The annual rainfall in Tempe, Arizona and the amount cost of tuition at Yale University.
C. The amount of time studying math and grade on a math test.
D. The amount of rainfall and the height of the grass

C. The amount of time studying math and grade on a math test.