Questions Refer to the Following Research Study

Multiple Choice

Questions refer to the following research study:
Ronda would like to assess the effects of a reading comprehension course on the scores of students. She gives a group of remedial students a reading comprehension pretest and then randomly assigns them to either the treatment group or the control group. Shortly after the treatment, she measures their reading comprehension scores again.
-How has Ronda controlled for the selection threat to internal validity?

A) She has randomly assigned participants to groups.
B) She has given a reading comprehension pretest.
C) She has given a reading comprehension posttest.
D) She has administered a treatment.