Of the Following, Which Is the Best Example of a Comparative

Of the following, which is the best example of a comparative case study?

A) Josh compares the results of two studies conducted on the outcomes of environmental education programs.
B) Maricella compares the experiences of two different families as they cope with medical decisions related to their newborn children.
C) Kenya compares the self-reported family dynamics between male and female single-parent families
D) Nadia examines the differences between student writing outcomes between those provided personal laptops in school and those who are not provided laptops