During the extraction of iron in the blast furnace ,
A. Coke acts as reducing agent in the lower zone and CO acts as reducing agent in the upper zone
B. CO acts as reducing agent in the lower zone and Coke acts as reducing agent in the upper zone
C. Coke acts as reducing agent in the lower zone and CO acts as oxidising agent in the upper zone
D. CO acts as reducing agent in the upper zone and Coke acts as reducing agent in the upper zone
