The chemical combination of substances that results in the formation of water is represented by option:
C. Hydrogen + oxygen
When hydrogen gas (H₂) reacts with oxygen gas (O₂), it forms water (H₂O). The chemical reaction can be written as:
\[ 2H_2 + O_2 \rightarrow 2H_2O \]
The other options do not directly yield water as a product.