Answer:
Element, element, Compound.
Explanation:
The element carbon combine with element oxygen to form compound carbon dioxide.
Option c is correct because,
Carbon (C) and oxygen (O) are elements when they combine they produces CO₂. Carbon dioxide is a compound not a mixture, because the properties of carbon dioxide are different from element oxygen and carbon. If they retain their properties after reaction or combining CO₂ would be a mixture but actually its not happens. The properties of carbon dioxide are different.
Mixture:
When two or more substances combined through physical forces in such a way that they retained their properties the resultant substance is called mixture.
Compound:
When two or more substances chemically bonded together and form a compound which have different properties from constituents it is called compound.