Final answer:
If Lorenzo parks on the sidewalk and receives a ticket, he would have a negative payoff of $100. The opportunity cost of searching for parking is $30 per day.
Step-by-step explanation:
The negative payoff that Lorenzo would end up with if he got a parking ticket is $100. This means that if Lorenzo parks on the sidewalk and receives a ticket, he would have a negative payoff of $100. The opportunity cost of searching for parking is $30 per day, so if Lorenzo chooses to search for parking, he is giving up the potential gain of $30 he could have earned doing something else.