Which of the following is a free living, effective biocontrol agent, found very often in the root ecosystem?

Trichoderma

The correct answer is Option (1) → Trichoderma

A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma. Trichoderma species are free-living fungi that are very common in the root ecosystems. They are effective biocontrol agents of several plant pathogens.