Step 1: Concept
This is a critical safety parameter for fuels and lubricants used in agricultural machinery.
Step 2: Meaning "Ignitable" means the vapor will catch fire momentarily when an ignition source is introduced.
Step 3: Analysis
The flash point indicates the volatility and flammability risk of the liquid. The fire point is typically higher, where the liquid continues to burn.
Step 4: Conclusion
The defined term is the Flash point.
Final Answer: (C)