What are bio-pesticides?

Assertion $A$: The use of biocontrol agents prepared by microorganisms has become necessary as an alternative to chemical pesticides.
Reason $R$: The use of biological control agents helps maintain the balance of the ecosystem.
Which option is correct for Assertion $A$ and Reason $R$?

Match the following columns correctly:

Column-$I$	Column-$II$	Column-$III$
$(a)$ $B.T.$ bacteria	$(p)$ Free-living fungi	$(i)$ Arthropods
$(b)$ Trichoderma	$(q)$ Bionematicides	$(ii)$ Cereal crops
$(c)$ Baculovirus	$(r)$ Cotton	$(iii)$ Crop-sucking pests
$(d)$ Pseudomonas	$(s)$ Symbiotic fungi	$(iv)$ Nematodes
	$(t)$ Quantum-$4000$	$(v)$ Crop disease control
	$(u)$ Biological control

$A$ major pest eradicated through the release of sterile males is:

Which one of the following is a genetically improved bacterium used for pollution control?

Which fish controls diseases like malaria and filariasis by feeding on mosquito larvae?