Democracy’s superior virtue lies in the fact that it calls into activity

(a) the intelligence and character of ordinary men and women.
(b) the methods for strengthening executive leadership.
(c) a superior individual with dynamism and vision.
(d) a band of dedicated party workers.

NEW NCERT Class 8 Civics, Chapter 3, page 32

The take-off point for a democracy is the idea of consent, i.e. the desire, approval and participation of people. It is the decision of people that creates a democratic government and decides about its functioning.
So, since democracy requires voters’ decision making- hence intelligence and character are called in.