RNA Vaccines Have Shown Promise but Have Yet to Be

RNA vaccines have shown promise but have yet to be tested in humans. However, further evidence needs to be collected before human clinical trials can begin. Which would be the best experiment to perform to test the efficacy of an RNA vaccine against Zika virus in mice?

A) Give one group of healthy mice the vaccine. Then infect the mice with the Zika virus and test their blood for the presence of Zika virus.
B) Give one group of healthy mice the vaccine and another healthy group a placebo. Then infect both groups with the Zika virus and test their blood for the presence of Zika virus.
C) Give one group of mice already infected with Zika virus the vaccine and another healthy group a placebo. Then infect the healthy group with the Zika virus and test the blood of both groups for the presence of Zika virus.
D) Give one group of mice already infected with Zika virus the vaccine and another group already infected with the Zika virus a placebo. Then test the blood of both groups for the presence of Zika virus.