20. The following table lists the number of days that five houses had been up for sale, as well as their selling price.

X (days)

45

12

3

17

32

Y (1000$)

275

401

420

212

365

Calculate the correlation coefficient r between the number of days (X) and the selling price (Y) for this sample.

a) - 0.465

b) - 0.219

c) + 0.219

d) + 0.512

e) + 0.897