Answer:
A) because they were not vaccinated.
Explanation:
Measles is a dangerous and highly contagious disease, which is characterized by high fever and spotting on the body. Our body has no natural defenses against this disease, and the most efficient way of not being infected by it is through vaccines.
Measles has gone years without being a real threat to humanity, but unfortunately the anti-vaccine movement has grown worldwide. This movement meant that many parents did not allow their children to get the measles vaccine, which made them susceptible to the disease that once again threatened humanity, especially in countries like the USA and Brazil, for example.
