Answer: Option (a) is the correct answer.
Step-by-step explanation:
A compound is defined as the substance which contains different type of elements that are chemically combined together in a fixed ratio by mass.
For example,
is a compound as it contains carbon and hydrogen atoms which are different elements. And, both C and H atoms are combining in 1:4 ratio.
A compound can be chemically broken down into its constituent particles.
An element is defined as the substance that contains only one type of atoms.
For example, element C contains only atoms of carbon.
Thus, we can conclude that out of the given options
is a compound that contains carbon.