Answer:
The correct answer for chlorine is Option C.
The correct option for carbon dioxide is Option B.
Step-by-step explanation:
Element is defined as a chemical substance which cannot be broken down into simpler substances by any chemical means.
Compounds are defined as a chemical substance which can be broken down into simpler substances by chemical means. It is made up from two or more different elements.
Mixture is defined as the substance which is made by the combination of two or more different materials in such a way that no chemical reaction occurs.
From the above information:
Chlorine is an element because it is the simplest substance. Hence, the correct option for this is Option C.
Carbon dioxide is defined as the compound because it is made from two elements and can be broken down into simpler substances. Hence, the correct option for this is Option B.