children for whom vaccinations are ineffective are unlikely to contract the disease. Suppose someone says: $"$If most children are getting vaccinated, why does it matter if I don't get my children vaccinated?"

a$.$ Is "herd immunity" a public good?

Herd immunity is

A$.$ a public good because a person receives some immunity from the disease by being vaccinated, even if other people are not vaccinated.

B$.$ a public good because immunity is nonexcludable, and everyone can simultaneously enjoy the "herd immunity."

C$.$ not a public good because immunity is nonexcludable, but in order for it to occur there must be a herd, and there is no guarantee that enough people will get vaccinated.

D$.$ not a public good because not everyone can consume herd immunity whether or not they pay for it$.$

b$.$ What does "free riding" mean? Is the person asking the question attempting to free ride?

In referring to a "free ride," the person means that some people may

A$.$ be able to get the vaccine for free.

B$.$ be able to take advantage of herd immunity if many other people are vaccinated.

C$.$ not be able to pay for the vaccine and won't get it$.$

D$.$ not want to get the vaccine because there is a cost in time and inconvenience in getting vaccinated.

What will be the effect of this free riding on vaccination rates against measles?

If the person is correct, the effect of this free riding would be

A$.$ a scientific study on the benefits of vaccinations.

B$.$ a breakdown in herd immunity so that diseases that would otherwise be rare could become common.

C$.$ an increase in government spending on vaccines.

D$.$ a demand for more subsidies for vaccinations.

c$.$ Every U$.$S$.$ state requires that children be vaccinated against measles before enrolling in kindergarten because

A$.$ the costs are known and the benefits are unknown.

B$.$ it is required by every workplace.

C$.$ they believe the benefits to them of being vaccinated outweigh the costs.

D$.$ the benefts are known and the costs are unknown.