What is the group of 4 elements?

Excuse me, could you please clarify what you mean by "the group of 4 elements"? Are you referring to a specific concept in chemistry, physics, or another scientific discipline? Could it be the four basic elements of nature, such as earth, air, fire, and water? Or perhaps you're talking about a group of four chemical elements that share similar properties or play a specific role in a chemical reaction? If you could provide a bit more context or clarify your question, I'd be happy to give you a more accurate answer.