The sentences given below, when properly sequenced, form a coherent paragraph. Each sentence is labelled with a letter. Choose the most logical order of sentences from among the given choices to construct a coherent paragraph. (A) Payment for imports and exports is made through a system called foreign exchange. The value of the money of one country in relation to the money of other countries is agreed upon. (B) The rates of exchange vary from time to time. (C) For example, an American dollar or a British pound sterling is worth certain amounts in the money of other countries. (D) Sometimes a US dollar is worth 60 rupees in India.