Answer:
The opportunity Cost is $72,000
but reviewing the impact the studio has on the store sales will give better deep dive in concluding this decision.
Explanation:
Opportunity cost is income foregone at the expense of a decision taken
In this case, it easy to see the foregone decision is "not renting" out the space used for the fitness studio
The income this would have generated is $6,000 x 12 months = $72,000
However, the question doesn't provide for us how much of an influence the fitness studio has on the sports store. In other words, if the % of the Studio users contribute a significant amount in Sales from the store, then closing down the studio would not make the $468,000 profit realizable in the coming years.