Which of the following compound is used tor estimation of CO?

The measurement of carbon monoxide uses iodine peroxide ${\mathrm{I}}_2{\mathrm{O}}_5$.

The measurement of carbon monoxide uses iodine peroxide [I2O5].

When solid iodine and carbon dioxide (CO2) are combined into iodine peroxide (I2O5) and gaseous carbon monoxide (CO) in the presence of air.

What happens chemically is:

${\mathrm{I}}_2{\mathrm{O}}_5+5\mathrm{CO}\to {\mathrm{I}}_2+5{\mathrm{CO}}_2$