Primary air pollutants are those that are directly emitted into the atmosphere from various sources. They have a significant impact on air quality and can cause various environmental and health problems. Among the given options, option 'C' is the correct answer as it includes sulfur oxide and hydrocarbon as primary air pollutants. Let's understand each of these pollutants in detail:

Sulfur Oxide:
- Sulfur oxide refers to compounds containing sulfur and oxygen atoms. The two primary sulfur oxides are sulfur dioxide (SO2) and sulfur trioxide (SO3).
- It is mainly produced from the combustion of fossil fuels, such as coal and oil, in power plants, industrial processes, and vehicles.
- Sulfur oxide emissions contribute to the formation of acid rain, which can damage ecosystems, harm aquatic life, and corrode buildings and infrastructure.
- Inhalation of sulfur dioxide can irritate the respiratory system, cause breathing difficulties, and worsen existing respiratory conditions such as asthma.

Hydrocarbon:
- Hydrocarbons are organic compounds composed of hydrogen and carbon atoms. They are released into the atmosphere from various sources, including incomplete combustion of fossil fuels, industrial processes, and natural sources.
- Hydrocarbons play a role in the formation of ground-level ozone and contribute to the formation of smog.
- They are also a significant contributor to the greenhouse effect and climate change.
- Some hydrocarbons are toxic and can have adverse health effects when inhaled. They can cause respiratory problems, eye irritation, and even cancer in high concentrations.

Considering the above information, it is clear that sulfur oxide and hydrocarbon are primary air pollutants that have significant environmental and health impacts. Their emissions need to be controlled through various measures such as the use of cleaner fuels, improved industrial processes, and the implementation of emission control technologies to ensure better air quality and reduce their harmful effects.