While DrBartlett Effectively Controlled for Confounding Variables in His Experiment, the the Results

Multiple Choice

While Dr.Bartlett effectively controlled for confounding variables in his experiment, the results do not generalize to the real-world.This means Dr.Bartlett's research has:

A) neither internal validity nor external validity
B) low internal validity, but high external validity
C) high internal validity, but lacks external validity
D) high internal validity and high external validity