The results of a recent poll on the preference of shoppers regarding two products are shown below.

Product	Shoppers Surveyed	Shoppers Favoring This Product
A	700	420
B	800	456

The 95% confidence interval estimate for the difference between the populations favoring the products (Product A - Product B) is _____.

a. -0.020 to 0.080

b. 0.50 to 0.60

c. 0.020 to 0.60

d. 0.03 to 0.40