Answer:
Opportunity cost relating to time
Explanation:
Opportunity cost refers to the benefits foregone of a non chosen option when a choice is made and an option is chosen.
The concept of opportunity cost relates to the sacrifice made of one option to pursue another option since both cannot be chosen at a time.
In the given case, Mr Brown is desirous of attending a musical concert but is scheduled to work for the same time and duration as the concert. So he can either work or go for the concert. Attending the concert would mean loss of income for hours worked instead.
