Step 1: Concept Stoves (regenerators) are auxiliary structures of a blast furnace used to improve thermal efficiency.
Step 2: Meaning They utilize the latent and sensible heat of the blast furnace top gas to heat up a medium.
Step 3: Analysis Cold air is blown through the heated bricks of the stove before it enters the furnace through the tuyeres.
Step 4: Conclusion Thus, the primary function of blast furnace stoves is the preheating of the air blast.
Final Answer: (C)