You have collected data for the 50 U.S. states and estimated the following relationship between the change in the unemployment rate from the previous year and the growth rate of the respective state real GDP ​(​). The results are as​ follows: ​

Δur= (0.12) -(0.04)x gy, R2= 0.36, SER= 0.78

Assuming that the estimator has a normal​ distribution, the​ 95% confidence interval for the slope is approximately the​ interval:

a. [-0.31, 0.15]
b. [2.57, 3.05 ]
c. [-0.33, - 0.13]
d. [-0.13, -0.15]