Out of C and CO, which is a better reducing agent at 673 K?

Explanation

The following reactions take place, when carbon and carbonmonoxide acts as a reducing agent.
(i) `{:(2C + O_2 , to , 2CO),(C + O_2, to , CO_2):} implies` Carbon as reducing agent.
(ii) `2CO + O_2 to 2CO_2 } CO` is reducing agent.
From Ellingham diagram, at temperature 673 K, the free energy change of the formation of `CO_2` from `CO` is more negative than the formation of `CO` or `CO_2` from carbon. Hence, at 673 K, CO is better reducing agent than carbon.