In a well-known karaoke club, a professional singer was

In a well-known karaoke club, a professional singer was hired to assist guests who had trouble staying in tune with the songs they were attempting to sing. On the first night, this caused discomfort to many of the guests who upon hearing their voices alongside that of the professional, suddenly lost confidence and felt embarrassed. On the second night, the number of singing guests who felt embarrassed by the professional's assistance was lower. Therefore, the club should not cease the employment of the professional singer, as in time the guests' discomfort will have diminished completely.

The author's conclusion relies on which of the following assumptions?

A) The popularity of a karaoke club does not depend on the standard of vocal capability displayed by the guests.
B) Employing a professional singer is not necessarily expensive.
C) The suggestion to hire a professional singer was first made by the guests themselves.
D) The guests' discomfort is caused by low self-esteem and a habit of comparing themselves with others.
E) Most of the guests visiting the club are returning customers.

OA E

Source: Economist GMAT