Reliability and validity in measuring personality traits

A. Choose one of the three methods of personality assessment listed below and indicate what factors might limit its reliability and validity.
B. If you had to argue for the superiority of one of these methods over the others, which one would you choose and why?
1. self reports from the persons being assessed
2. reports from close friends and relatives of the person being assessed
3. observations of the person being assessed by a trained observer.