Laura is designing a study that examines difference in social skills between children raised in a three—generation family household compared to those raised in a two-generation family home. Laura is most likely to study this research problem by use of causal-comparative research because
a. the events have already happened.
b. she will not attempt to explain any reasons for differences in social skills.
c. she wants to manipulate the independent variable, type of home environment.
d. she will only address relationships and not levels of an independent variable.