Which of the following is true? 

a. Since 2000, the amount of foreign aid toward global development that wealthy countries have contributed (relative to their wealth) has increased. 

b. Since 2000, the amount of foreign aid toward global development that wealthy countries have contributed (relative to their wealth) has decreased. 

c. As a percent of its national income, the United States leads developed countries in donating foreign aid. 

d. All eight of the Millennium Development Goals established by the United Nations in 2000 had been reached by the year 2015.