The origin of Quasars? Monster Black holes central in Galaxy Clusters.
According to Q-FFF Theory, normal black holes repel propeller shaped fermions ( spinning rigid strings, with a Calabi yau surface) by the large curvature angle of the horizon,
Then Monster black holes seem to eat fermions a go go- caused by the much smaller Schwarzschild horizon curvature- angle and as a consequence become a Quasar eating all the stuff around in contrast with ejecting all femion plasma into two jets..
http://www.astronomy.com/news/2019/12/this-huge-galaxy-has-the-biggest-black-hole-ever-measured?
Question: What is the minimum black hole horizon radius to change a black hole into a Fermion eating Quasar?
At least, less than the Abell 85 BH: 40 billion the mass of the sun, which is in line with present estimates of Quasars: Wikipedia: A Quasar is an extremely luminous active galactic nucleus (AGN), in which a supermassive black hole with mass ranging from millions to billions of times the mass of the Sun.
The smallest Quasar seems to be: PKS 0405-385. with a radiation peak variability less than an hour.