Final answer:
Cooling fans are responsible for maintaining proper airflow and keeping dust and smoke out of the computer case.
Step-by-step explanation:
The components that assist in maintaining proper airflow and keeping the dust and smoke out of the case are c) Cooling fans. These devices are essential for preventing overheating in electronic systems by moving air across components such as the CPU, GPU, and other heat-generating parts. In contrast, heat sinks are used to dissipate heat away from individual components, power supplies provide electrical power to the system, and motherboards are the main printed circuit boards that connect and communicate between all other parts of the computer.