In the Study by Siminoff,Burant,and Ibrahim Entitled "Racial Disparities in Preferences

In the study by Siminoff,Burant,and Ibrahim entitled "Racial Disparities in Preferences and Perceptions Regarding Organ Donation," sampling was done using a random digit telephone technique.What threats to internal validity does this prevent?

A) Selection effects
B) Selection bias
C) Social desirability bias
D) Testing effects