3 molecules of oxygen (O2) react with 6 molecules of carbon monoxide (CO) to produce some amount of carbon dioxide (CO2)

6 molecules of CO2

Explanation:

3 (O2) + 6 (CO) > ? (CO2)

There's 12 oxygens, and 6 carbons in the reactant. You can put 6 as the coefficient of the product to get the same amount on the left as the right.

b is the correct

elements make up everything, and they combine to make compounds.

the answer is c