Answer: b.Correctly ignored a sunk cost
Step-by-step explanation:
Sunk costs are those that are already incurred and should not have any influence on the decision to be made.
The cost of the ticket to the play has already been incurred and could not be sold, exchanged or transferred so was a sunk cost. By going to the concert with Simone, Ravi decided to ignore a sunk cost and he was correct to do so.