What does "trade balance" refer to?

"Trade balance" specifically refers to the difference between the value of a country's exports and imports. This metric is a crucial indicator of a country's economic health and its relationship with the global market. A positive trade balance, where exports exceed imports, suggests that a country is selling more to other nations than it is buying from them, potentially indicating a strong economy. Conversely, a negative trade balance occurs when imports surpass exports, which may raise concerns about economic sustainability and dependence on foreign goods and services.

The other options do not accurately capture the concept of trade balance. The availability of goods for trading, the number of agreements signed, or the value of foreign investments pertain to different aspects of trade and economics but do not define the trade balance itself. Thus, option B is the correct choice, as it encapsulates the fundamental definition of trade balance accurately.