Use the Information Below to Answer the Following Question

Use the information below to answer the following question.
Fact 17.2.1 Should Childhood Vaccines Be Mandatory?
While Canadian vaccination rates are high, the outbreaks of measles in five provinces during 2014 show that not everyone is getting them. There is no national policy making vaccinations mandatory, although Ontario, New Brunswick and Manitoba require public school students to show their immunization records to attend school.
Source: CBC Radio, April 15, 2014
-Refer to Fact 17.2.1. Someone who doesn't get vaccinated against measles is a "free rider" because if everyone in a neighbourhood except one person gets vaccinated, then the unvaccinated person

A) defeats the principle of minimum differentiation.
B) benefits from the neighbours' vaccinations.
C) increases the risk of his neighbours getting measles.
D) changes the measles vaccination into a natural monopoly good.
E) changes the measles vaccination into a common resource.