Where Do Economic Agents,such as Individuals,firms and Nations,interact with Each

Multiple Choice

Where do economic agents,such as individuals,firms and nations,interact with each other?

A) In public locations monitored by the government.
B) In any arena that brings together buyers and sellers.
C) In any location where people can physically get together to buy and sell goods, such as shopping malls.
D) In any location where transactions can be monitored by consumer groups and taxed by the government.