Behavioral theorists claim that scientific psychology should study observable behaviors in order to adequately understand human tendencies.
Behavioral scientists are the persons who are engaged in specific behaviors influenced by some factors.
Scientific psychology is defined as the science which benefits society and enhances our lives.
Observable behavior is the physical activities performed by an individual which is recorded by the observer.
Adequately means sufficiently.
Understand means to perceive the intended meaning.
Human tendencies means the behavior of a human being.
Hence the option (D) is correct.
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