Answer:
iodine
Step-by-step explanation:
A compound is a pure substance that is formed from the combination of two or more elements. Compound can usually be split into smaller constituents by chemical process. Example of a compound is water . Water contains 2 different elements which are hydrogen and oxygen. The water molecule can be split into it constituent elements by hydrolysis. The properties of a compound is usually different from the constituent elements that formed it.
Any substance that contains only one kind of atom is known as an element. An element cannot be broken into simpler substance by a chemical process.
All other options are compound except for iodine which is an element. Iodine is an element as it contains only one type of atom. Therefore, it cannot be separated,. Methane(CH4), Ethanol and alcohol is a compound that contains two or more element that can possibly be split into it constituent element.