What two things does the engine of a quasar contain?
The engine of a quasar consists of a supermassive black hole and a ready supply of gas and dust.
Quasars typically form in young galaxies. Most galaxies have a supermassive black hole at their centres. When there is a ready supply of material near the black hole it starts to fall into the black hole forming an accretion disc.
It takes a long time for material to fall into a black hole. So, as more and more material falls into the accretion disc it gets superheated by friction and gravity to the point where it emits huge amounts of radiation.
So, the supermassive black hole and material falling into it are the two components of a quasar's engine.