Answer:
Here Sample Survey is used.
Explanation:
Since, they did not survey on all mice only the dozen mice are used in the survey. So, here Sample Survey methodology is used.
The sample is a subset of the population. We take samples because it is easy to analyze samples as compared to population and it is less time taken. Further, the sample is said to be best sample if it is the representation of the whole population.
Further, here Case-Control Study is used. Since drug tested mice are compared with normal mice.