Social media, such as the online social networking portal Meetup, have increased the likelihood of people forming social tribes by reducing the transaction costs associated with forming such groups.

In part, a country's current account measures

A) its current debt as opposed to its long-term debt. B) borrowing and lending activity between the country's residents and foreigners. C) net increases and decreases in a country's holdings of foreign currency. D) receipts from the sale of goods and services to foreigners and payments for goods and services bought from foreigners.

Examples of comparative advantage show how trade between two countries can make each better off. Compared to their pre-trade positions, trade makes both countries better off because in each country

A) total employment is greater. B) total consumption of goods is greater. C) wages are higher. D) total welfare is greater.