Lisa is planning a field investigation and needs to manipulate variables to test her hypothesis. Which of the following BEST describes what she is applying?

A. a controlled treatment to observe the effect on the independent variable
B. an experimental treatment to observe the effect on the independent variable
C. a controlled treatment to observe the effect on the dependent variable
D. an experimental treatment to observe the effect on the dependent variable

B. an experimental treatment to observe the effect on the independent variable