Final answer:
To examine an intensive property of a rectangular block of wood, determining the density is the correct approach, as density is inherent to the material and independent of the sample size.
Step-by-step explanation:
To examine an intensive property of a rectangular block of wood, the student should choose option D) Determine the density. Density is an intensive property because it does not change with the amount of substance; it is inherent to the material itself. The density of a substance can be calculated by dividing its mass by its volume. Mass is typically measured using a balance, and volume can be determined by calculating the product of the block's length, width, and height.