The 150.00 Naira which Olu would have used to purchase a textbook was used to buy a T-shirt . This implies that
Answer Details
When Olu chose to use the 150.00 Naira to buy a T-shirt instead of a textbook, he had to forgo the opportunity of buying the textbook. This forgone alternative is referred to as the opportunity cost. Therefore, Olu's opportunity cost of buying the T-shirt is the textbook he could have purchased with the same amount.
On the other hand, the 150.00 Naira used to purchase the T-shirt is Olu's money cost or actual cost. So, the statement "Olu's opportunity cost is the textbook" is the correct answer.