I belive the answer is Feudalism. It was used in Medievaltimes.
The best analogy that compares a relationship between synonyms or antonyms would be "<span>a. steal : take :: lend : loan" since synonyms and antonyms could be considered opposites, much like "stealing" and "loaning". </span>
The best and most correct answers among the choices provided by the question are the first choice or number 1, and the fourth choice or number 4.
Feudalism is a system of cooperation among peoples which was basically an exchange of gold for protection and a<span> knight may serve a vassal in exchange for land are statements that are not true.</span>
I hope my answers has come to your help. God bless and have a nice day ahead!