Explain why, hot air is blown into the blast furnace?

Plzzz i need it

i am going to put the answers in order i dint feel like typing it out so yeah

a

d

c

b

b

b

a

d

a

b

c

c

c

b

d

the correct answer would be d. hope this !

so she was walking and she stepped on warm jeffy , uh uh uhh dadye i just pooped my pants