As the Carbon Content in Steel Increases, Its Ductility Tends

Multiple Choice

As the carbon content in steel increases, its ductility tends to decrease.A researcher at a steel company measures carbon content and ductility for a sample of 15 types of steel.
Based on these data he obtained the following regression results. The 95% confidence interval for the slope of the regression equation is

A) -5.456 to -1.136
B) -4.393 to -2.199
C) 6.164 to 9.178
D) -5.666 to -0.926
E) 2.581 to 12.761