Which of the following is an advantage of bioreactor which uses continuous culture system rather than batch culture?

The transformed recombinant cells are allowed to grow in a large bioreactor till the maximum amount of biochemical has been formed 

The bioreactor has to be emptied, cleaved and filled again with culture medium and inoculum

There is regular drainage of the medium and culture cells from one side and additional fresh medium from the other side leading to higher yield of desired product

It provides required growth conditions (temperature, pH, substrate, salts, vitamins and oxygen)