In this particular scenario, the opportunity cost for Harry are the three activities he did not choose by going to his parent's house. His original plan of painting the apartment is the opportunity cost.
Harry, by deciding to go to his parent's house, missed out on three opportunities.
An opportunity cost refers to the loss of value, gain, or benefit that could be received from other options when one particular alternative is chosen.
In microeconomics, the alternative chosen over the other available alternatives yields higher value.
In this case, Harry missed out on three opportunities to visit his parent.
For Harry, in this context, visiting his parents was more important hence having higher value and benefit.
He simultaneously experienced loss of potential benefit and/or gain by not choosing any of the other available alternatives.
Therefore, the opportunity cost for Harry are the three activities he did not choose by going to his parent's house.
Explanation: usually when you see a group of men standing around each other, you would want to stay away from them because maybe they might be selling drugs or who knows what and you wouldnt want to walk right through them because they'll probably get mad you.