TEST 4  t 20

请问这一题具体应该怎么做啊？多谢！

Robert Lamy is an equity advisor. One day he gathered information about three microeconomic variables X, Y, Z. He noticed that whenever variable X increased by one unit, variable Y decreased by 0.3units but variable C increase by 0.3 units. The correlation between variables X and Y

And the correlation between variables X and Z, respectively, are closest to:

Correlation between Variables X and Y         Correlation between Variables X and Y

A   -0.3                                     1.0

B   -0.3                                     0.3

C   -1.0                                      1.0

D   0.3                                       -0.3

我觉得选C，答案是什么？