Which of These Is TRUE of the Ebola Vaccine

Which of these is TRUE of the Ebola vaccine?

A) No vaccine has been developed because no technologies exist to combat Ebola.
B) No vaccine has been developed because too few people have died from Ebola.
C) After people from developed countries were infected drug companies have made significant progress in developing a vaccine.
D) A successful vaccine has been developed and people are now routinely vaccinated.