Which of the following ores can be reduced by carbon?

a. Haematite           

b. Zincite          

c. Iron pyrites         

d. Sphalerite

Choose the correct option:
1. a and b
2. b and c
3. c and d
4. a and d

HINT: Oxide ore can be reduced by carbon.
STEP 1: In the metallurgical process, the oxide ores are reduced by carbon. Sulphide ore cannot be reduced by carbon.
Here, haematite Fe2O3 and zincite ZnO are oxide ores of iron and zinc respectively while iron pyrites FeS2 and sphalerite ZnS are sulphide ores of iron and zinc respectively.
STEP 2: The reactions involved are:
2Fe2O3(s) + 3C(s)  4Fe(s) + 3CO2(g)ZnO(s) + C(s) Zn(g) + CO(g) 
Therefore, haematite and zincite can be reduced by carbon.