ANS:B - Coke

The main source of sulfur in the blast furnace charge is coke. Coke is a primary fuel and reducing agent used in the blast furnace. It is derived from coal through a process called coking, which involves heating coal in the absence of air to drive off volatile components. During the coking process, sulfur present in the coal is concentrated in the coke. Sulfur in coke can contribute to sulfur dioxide (SO2) emissions during the iron smelting process. Excessive sulfur content in coke can lead to the formation of sulfur-bearing compounds, which can have detrimental effects on the quality of the iron produced, as well as on downstream processes such as steelmaking. While other materials in the blast furnace charge may contain sulfur to some extent (such as iron ore or sinter), coke typically contributes the most sulfur due to its high sulfur content and its large proportion in the charge composition. Therefore, coke is the correct answer as the main source of sulfur in the blast furnace charge.