Which of the following is an acceptable material for blocks used to position a body?

The use of non-absorbent material painted with enamel if made of wood is an acceptable choice for blocks used to position a body because it ensures hygiene and prevents the absorption of bodily fluids, which is crucial in a funeral setting. The enamel coating provides a protective barrier that enhances the wood's durability and makes it easier to clean and sanitize.

This choice aligns with regulations regarding maintaining sanitary conditions in funeral practices, which is critical to preventing potential health hazards and ensuring proper handling of remains. Other choices may not meet these sanitary standards; for instance, wooden blocks that are not treated could harbor bacteria and fluids. Additionally, while plastics might be a durable option, they might not provide the same stability as a well-prepared wooden block. Metal is also a viable material, but it may pose risks such as potential injuries to personnel due to sharp edges or could complicate the embalming process if not appropriately designed. Thus, non-absorbent wood with enamel is preferred for its combination of safety, stability, and hygiene.