Given the Following Design, Identify the Most Probable Example of the Study

Given the following design, identify the most probable example of the study from the options below. E X₁ O
C X₂ O

A) Susan compares mathematics achievement scores between those students who were given after school instruction and those who were not.
B) Susan compares self-esteem levels between children who are in ability grouped versus non-ability grouped classrooms.
C) Susan examines the relationship between school violence incidences and number of children in a typical class.
D) Susan describes how fathers and mothers feel about moral education curriculum legislation.