Answer:
Option a= one shot case study
Explanation:
One-shot case study is the experimental design in this question from the options that has the smallest number of participants. In One-shot case study, there is no randomization and it deals with only a group.
In correlation experimental design requires more than one group for analysis. At least, in correlation experimental design, two variables are compared and contrast to define or explain a subject.
In QUASI- experiment design; in this design you have to group variables so, you need many participants too.
In posttest-only control group, for the analysis one will be needing more than one group.
