Question: A patient comes to the clinic for general malaise and yellowing of the skin and his doctor suspects that it is a hepatitis A picture. Which of the following answers constitutes the most accurate and safest factor to determine the pre-test probability ( before carrying out any study) of what is said table? 
 Options:  <1> Intensity of jaundice. <2> Frequency of hepatitis A in the environment. <3> Days of duration of the painting. <4> Professional experience on jaundice pictures. <5> Previous illnesses of the patient.
2