Which of the following options is a type of explosive odor?

Sodium chlorate is associated with an explosive odor because it is a powerful oxidizing agent that can react vigorously with combustible materials, leading to the formation of potentially explosive mixtures. Unlike the other substances listed, sodium chlorate is specifically used in the production of explosives and pyrotechnics due to its ability to boost combustion processes.

MDMA and cocaine are both controlled substances known for their psychoactive effects but do not possess characteristics associated with explosive odors. Similarly, marijuana, while it has a distinct odor, is not related to explosive materials. Understanding the specific chemical properties and uses of these substances is crucial in recognizing the correct answer in the context of explosive odors and safety.