Final answer:
The angle of repose for red iron oxide is not provided in the given information, so the correct answer cannot be determined.
Step-by-step explanation:
The angle of repose is the maximum angle at which a material can be placed without moving down-slope. It varies for different types of materials and moisture conditions. The angle of repose for red iron oxide is not provided in the given information, so the correct answer cannot be determined. Therefore, none of the options A, B, C, or D can be considered as the angle of repose for red iron oxide.