How Did Europe's Emissions Trading Scheme Work

Multiple Choice

How did Europe's Emissions Trading Scheme work?

A) European countries banned trade with firms that polluted in excess of their allowances.
B) European countries traded new antipollution technology to firms in developing countries that committed to reducing carbon emissions.
C) Firms were initially given allowances for greenhouse gas emissions that they could sell or buy depending on their own efficiency.
D) European governments gave tax credits to firms that reduced their carbon emissions.