What voting system is preferred by voting rights activists as a means of increasing minority representation?

Cumulative voting

Explanation:

Cumulative voting - in this type of voting system sole right is given to shareholder who is in minority to elect their director. this system permit shareholder to cast all their vote for any single nominee for board of directors.

while in regular voting system no permission is granted to anyone to cast more than one vote.

example - for four member and 500 holding share, maximum vote than can cast is 500 (one vote for one share) in normal voting but in cumulative maximum that can cast is 2000 votes