Concept:Tourism is a service, and services are counted as invisible trade in a country's balance of payments.
Explanation:The balance of payments is divided into visible trade, which covers physical goods, and invisible trade, which covers services.
When foreigners visit a country, they spend money on services like hotels, transport, and sightseeing.
These are not physical goods, so they cannot be placed under merchandise trade.
Thus, tourism earnings are recorded under invisible trade.
Answer:B. invisible trade