Timber industry is?

• A. An industry focused on the cultivation, harvesting, and processing of trees for wood products.
• B. A branch of mining.
• C. A system of log grading.
• D. A type of lumber grade.

Answer: (D)

Timber industry refers to the sector that covers growing forests, harvesting trees, and turning them into wood-based products. It spans the whole value chain—from forest management and logging to milling and producing items like lumber, plywood, and other wood goods, and then distributing them to markets. This broad view is what the best choice conveys: it centers on cultivation, harvesting, and processing of trees for wood products.

The other ideas miss the full scope. Mining deals with extracting minerals, not wood. A system of log grading is just one quality-control step used within processing, not the whole industry. A lumber grade is a quality category for finished wood, not the industry itself.