A regression model is used to forecast sales based on advertising dollars spent. The regression line is y=500+35x and the coefficient of determination is .90. Which is the best statement about this forecasting model?a. For every $35 spent on advertising, sales increase by $1.
b. Even if no money is spent on advertising, the company realizes $35 of sales.
c. The correlation between sales and advertising is positive.
d. The coefficient of correlation between sales and advertising is 0.81.