For each problem, select the best response.

(a) The points on a scatterplot lie close to the line whose equation is $y = 8 x - 9$. The slope of the line is

A. -8
B. 17
C. 9
D. 8
E. None of the above.

(b) Fred keeps his savings in his mattress. He began with $550 from his mother and adds $75 each year. His total savings $y$ after $x$ years are given by the equation

A. $y = 75 + x$
B. $y = 75 + 550 x$
C. $y = 550 + 75 x$
D. $y = 550 - 75 x$
E. None of the above.

(c) Smokers don't live as long (on the average) as nonsmokers, and heavy smokers don't live as long as light smokers. You regress the age at death of a group of male smokers on the number of packs per day they smoked. The slope of your regression line

A. must be between -1 and 1.
B. will be greater than zero.
C. will be less than zero.
D. can't tell without seeing the data.