*$_A carbonaceous fuel (containing no H‚Äö√á√á or hydrocarbons) is burnt and the resulting flue gas contains 21% CO‚Äö√á√á. It means that?

No excess air has been used for combustion

21% excess air has been used for combustion

21% excess oxygen has been used for combustion

Complete combustion of fuel has taken place

*$_A carbonaceous fuel (containing no H‚Äö√á√á or hydrocarbo

1.	*$_A carbonaceous fuel (containing no H‚Äö√á√á or hydrocarbons) is burnt and the resulting flue gas contains 21% CO‚Äö√á√á. It means that?
A.	21% excess air has been used for combustion
B.	21% excess oxygen has been used for combustion
C.	Complete combustion of fuel has taken place
D.	No excess air has been used for combustion
Answer» D. No excess air has been used for combustion