What is the most important tool that a provider has when collecting

information to make a medical diagnosis

a$.$ Laboratory Tests $($X$-$rays, blood tests, etc$)$

b$.$ Physical Examinations $($taking temperature, measuring blood pressure, etc$)$

c$.$ Medical Histories $($medical interviews, conversations with the patient, etc$)$

d$.$ Chart Reviews $($past medical charts, previous test results, etc$)$