The statement that best supports the idea that viruses are non-living is d: "All viruses are composed of one nucleic acid and protein."
This is because viruses do not fit the criteria of being composed of cells, which is a fundamental aspect of the cell theory. The other statements (a, b, and c) emphasize the cellular structure of living organisms, while statement d highlights the simplicity of viruses, indicating that they lack the cellular organization found in living cells.