________ is a highly infectious disease that was thought to be eliminated in the United States until outbreaks in 2014 and 2015.

Explanation
c is correct
Measles is caused by a paramyxovirus and is transmitted through air and direct contact. The measles virus is highly contagious with 90% risk of infection in non-immunized individuals. However, there are effective vaccine series (Measles-Mumps-Rubella: MMR series) that can prevent measles. Recent measles outbreak is thought to occur due to delayed or missed MMR vaccinations in children.

a is incorrect
Although polio is a highly contagious disease caused due to poliovirus, this infection has been eradicated in the US since 1979.

b is incorrect
Smallpox is one of those highly contagious diseases that have been completely eliminated worldwide, since 1980. The last reported case of small pox in the US was in 1949. This was achieved due to large scale vaccination against the variola virus, the causative agent of smallpox.

d is incorrect
Chickenpox is highly contagious viral disease that has never been eradicated in the US. It is, however, preventable by vaccination. Symptoms include blister-like rashes all over the skin surface and itchiness. However, the mortality rate is considerably low for chicken pox.

How would you rate this answer and explanation?