Carbon (c) and hydrogen (h) are pure substances. each is made of only one type of atom, but carbon atoms are different from hydrogen atoms. carbon and hydrogen chemically combine to form methane (ch4) based on this information, a. carbon, hydrogen, and methane are all compounds. b. methane is an element and carbon and hydrogen are compounds. c. carbon and hydrogen are elements and methane is a compound. d. carbon, hydrogen, and methane are all elements