An Experiment Is Conducted in a Middle School

An experiment is conducted in a middle school.Students in the experiment group receive special tutoring in math while students in the control group participate in a regular math class.On the math achievement test at the end of the year,the students in the special tutoring group score higher on math skills than the students in the regular math class.A parent complains about the ethics of this experiment.What ethical issue would the parent likely raise?

A) The math skills test is inadequate.
B) The students in the regular math class are disadvantaged because they did not have tutor.
C) The experiment did not receive approval from school officials.
D) The random assignment of students to groups was unethical.