iron, oxygen, nickel, copper. sodium, potassium, gold, hydrogen. helium, neon, argon, krypton. carbon, hydrogen, oxygen, nitrogen.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Plants and animals are composed of organic compounds. Which of the following are the common elements found in organic compounds?
Possibilities:
- iron, oxygen, nickel, copper.
- sodium, potassium, gold, hydrogen.
- helium, neon, argon, krypton.
- carbon, hydrogen, oxygen, nitrogen.

carbon, hydrogen, oxygen, nitrogen.