The correct answer is C. Transactions in foreign exchange.
A Tobin tax is a small tax on all foreign exchange transactions. It is named after James Tobin, an American economist who proposed it in 1972. The tax is intended to discourage short-term speculation in foreign exchange markets, which can lead to volatility and instability in the global economy.
A Tobin tax would be applied to all transactions in foreign exchange, including both spot and forward transactions. The tax would be levied on the value of the transaction, and would be collected by the government of the country in which the transaction takes place.
The Tobin tax has been proposed as a way to reduce volatility in the global financial system. It is also seen as a way to raise revenue for development and other purposes. However, the tax has been criticized for being difficult to implement and for potentially having negative consequences for the global economy.
Export is the act of selling goods or services to another country. Import is the act of buying goods or services from another country. Sales is the act of selling goods or services to a customer within the same country.
A Tobin tax would not be applicable to exports or imports, because these transactions do not involve the exchange of foreign currency. A Tobin tax would only be applicable to transactions in foreign exchange, which are transactions that involve the exchange of one currency for another.