Refer to the diagram. The area that identifies the maximum sum of consumer surplus and producer surplus is:

The above figure shows the marginal social benefit and marginal social cost curves of chocolate in the nation of Kaffenia. At Kaffenia's efficient quantity of chocolate

A) total consumer surplus is zero. B) total producer surplus is zero. C) the sum of consumer surplus and producer surplus is zero. D) the sum of consumer surplus and producer surplus is maximized.

When the Social Security program was in its infancy in 1940, the ratio of workers to retirees was more than 150 to 1. Currently, the ratio of workers to retirees is

A) more than 300 to 1. B) 50 to 1. C) less than 3 to 1. D) an even 1 to 1.