In an area of the Great Plains, records were kept on the relationship between the rainfall (in inches) and the yield of wheat (bushels per acre). Calculate the linear correlation coefficient.

Rainfall (in inches) X 8.3 6.6 11.2 103 16.6 8.1 4.8 13.4 13.8
Yield (bushels per acre). y 55.5 512 63.8 64 874 542 36.9 81 83.8

a. 0.900
b. 0.998
c. 0.899
d. 0.981