While judging a personality pageant, raters gave high scores to contestants who were already famous because of their presence in popular T.V. serials or advertisments and tended to give low scores to those who were not so popular. This phenomena is called

Halo effect

The correct answer is Option (1) → Halo effect

The phenomenon described, where raters give high scores to contestants who are already famous and low scores to those who are less known, is called the Halo effect. This cognitive bias occurs when the perception of one positive quality (like fame) influences the perception of other qualities (like attractiveness or talent). In this case, the contestants' fame positively affected the judges' scores.