The correct answer to this open question is the following.
The free-rider problem prevents a private business from investing in the building of a city sidewalk in that the private company invests its money to make a profit. And if the company's financial projection indicates that making money is not feasible, the company won't participate in the project.
A free-rider is the person who benefits from service without paying for it. So if the city sidewalk would be used mostly by free-riders and the company does not see a profit in the investment, absolutely it is not going to participate.