PLEASE HELP FAST!!!!!
A college professor hypothesizes that readers will comprehend more when reading a graphic novel than when reading text with no illustrations. To conduct an experiment, the professor will assign some students to the control group with a reading assignment in paragraph form and other students to the treatment group with a reading assignment in graphic novel form. Afterwards, all the students will take a quiz about the reading.

Randomization is important when assigning the students to the treatment and control groups to ensure

A. that both groups are made up of students from the same class.
B. that the treatment group has more students to better test the hypothesis.
C. that each student does not know about the alternative version of the assignment.
D. that both groups are roughly equivalent with regards to students’ gender, reading ability, and study habits.