What do you understand by the term "Kerb in foreign currency dealings?

غیر ملکی کرنسی کے لین دین میں کرب کی اصطلاح سے آپ کیا سمجھتے ہیں؟

The exchange rate of currencies in the open market

The exchange rate of currencies determined by the State Bank of Pakistan

All sort of monetary dealings in foreigncurrencies within the stock exchange.

None of these

Kerb can represent both the unofficial stock market on which buying and selling operations are processed after marketplace closure, in addition to casual deals.
As a standard rule, such operations are processed through brokers on the order of customers when, for some purpose or other, their orders could not be processed at the stock market.