A solid solution in which the solute is a gas typically refers to a gas dissolved in a solid (usually a metal). In this case, hydrogen gas can be absorbed by palladium metal to form a solid solution, called palladium hydride. This is a well-known example of a gas being absorbed into a metal to form a solid solution. Palladium is particularly known for its ability to absorb hydrogen gas into its structure at certain conditions, forming a hydrogen-rich alloy.
The other options are not examples of solid solutions involving a gas as the solute. For example:
- \( \text{(A)} \) Oxygen dissolved in water is a gas dissolved in a liquid, not a solid solution.
- \( \text{(B)} \) Solution of camphor in nitrogen is a liquid-solute in gas-solvent solution.
- \( \text{(D)} \) Glucose dissolved in water is a solid dissolved in liquid, not a solid solution.
Thus, the correct answer is option (C) Solution of hydrogen in palladium.