Which of the following is the best example of the free-rider effect?

You and a friend take a road trip to Florida in your friend's car. You pay for the gas.

In exchange for tutoring your friend in economics, she helps you with your geometry assignment.

You have paid for a streaming television service, and several of your buddies show up unannounced to watch it at your place.

You buy your date dinner, but your date insists on leaving a tip for the server.

A local Girl Scout troop is giving a "free" carwash. You give them a \(\$ 5\) donation.