Which economist gave the theory of Opportunity Cost?

Question:-

Which economist gave the theory of Opportunity Cost?

Answer:-

• Gottfried Haberler gave the theory of Opportunity Cost.
•  Opportunity Cost  is a key concept in economics, and has been described as expressing ''the basic relationship between scarcity and choice.
  
• The  Opportunity Cost of a product or service is the revenue that could be earned by its alternative use.
• In other words, the opportunity cost is the cost of the next best alternative for a product or service.