Explanation:

Let's break down the sentences and the options.

- Sentence C: "A large part of Canada is covered with coniferous trees." This is a good starting point since it establishes the natural backdrop.

- Sentence B: "Forest products, therefore, have been important export items of Canada for more than a century." This follows logically from the vast forest cover, indicated by the word "therefore."

- Sentence D: "Pulp and paper are the two most important forest products." This identifies the specific products that are pivotal to Canada's forestry.

- Sentence A: "Canada accounts for nearly one-third of the world's production of news print." This amplifies the significance of Canada's pulp and paper industry globally.

Now, evaluating the options:

- Option 1 (ABCD) doesn't logically flow from big picture to specific.

- Option 2 (DCAB) starts with specific products, then goes to forest coverage and exports, which is out of order.

- Option 3 (CBDA) flows logically from forest cover to export significance, then specific products, then global impact.

- Option 4 (BACD) displaces the issue of forest coverage, making it less effective at introducing the topic.

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