What did Watson state that psychologists should study

A)  only the things that people or other animals do, because those are observable behaviours 
B)  only the things that people do as a result of experience, because reflexes are not valid behaviours 
C)  things that people do, think, and feel 
D)  only the things that people think and feel, because those are psychological processes

Observable Behaviours

Actions or reactions of an individual, in response to external or internal stimuli, that are visible and measurable.

Psychological Processes

Internal operations that underpin cognitive functions such as perception, memory, and thinking.

Reflexes

Automatic, involuntary responses to specific stimuli, such as pulling a hand back from a hot surface, which occur without conscious control.