summarize in brief

(b) Private Good: A private good is both excludable and rivalrous. This means people can be prevented from using it, and one person's use reduces its availability to others. Example: A sandwich is a private good because if one person buys and consumes it, it is not available to others, and anyone who hasn't purchased it can be excluded. (c) Quasi-Public Good: A quasi-public good is one that is excludable but non-rivalrous, at least up to a point. fxampf'e: A toll road is a quasi-public good because people can be excluded if they don't pay, but one person's use does not significantly reduce its availability to others unless there is congestion. Public Good: A public good is non-excludable and non-rivalrous, meaning no one can be prevented from using it, and one person's use doesn't diminish its availability to others. Example: National defense is a public good because it protects all citizens, and one person's protection does not reduce the protection available to others