The sentences given in each question, when properly sequenced, from 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.

The correct option is A C B D.

Let's break down the logical flow of the sentences step-by-step to construct a coherent paragraph:

1. Sentence (A) serves as the introductory statement. It introduces the main subject—how payment for imports and exports is made using a system called foreign exchange—and establishes the fundamental concept of agreeing upon the value of one country's currency relative to another.

2. Sentence (C) directly illustrates the concept introduced in sentence (A) by providing a general example. It explains that, for example, an American dollar or a British pound is worth certain amounts in other currencies.

3. Sentence (B) builds upon the general concept of currency values by adding an important qualification: exchange rates are not static and vary from time to time.

4. Sentence (D) provides a specific, concrete instance of a fluctuating exchange rate (a US dollar being worth 60 rupees in India at a given time), following naturally after sentence (B)'s mention of variations over time.

Therefore, the most logical and coherent order of the sentences is A C B D.