Which of the following best describes control, a principle of experimental design?
O A. The separation of experimental subjects into groups that are as
similar as possible to control the effects of lurking variables
B. The selection of experimental subjects from a large group of units
or subjects, and then randomly assigning members to treatment
and control groups using either a random number generator or a
random number table
C. An experiment that features many groups of subjects as well as
different kinds of tests, if possible
D. A feature of an experiment designed to isolate the variable under
observation