In an Experiment, Control Over Extraneous Variables, Such as the Time

Multiple Choice

In an experiment, control over extraneous variables, such as the time of day or the temperature of the room, can be obtained by

A) using a double-blind experiment.
B) making all conditions except the independent variable exactly the same for all subjects.
C) using repeated measures.
D) observing and recording the impact of each variable on each subject in the experiment.