Match the columns:

Column-$I$	Column-$II$
$(a)$ Ladybird	$(1)$ Methanobacterium
$(b)$ Mycorrhiza	$(2)$ Trichoderma
$(c)$ Biocontrol	$(3)$ Aphids
$(d)$ Biogas	$(4)$ Glomus

(A) The correct matches are as follows:
$(a)$ Ladybird is a beetle used to control $(3)$ Aphids.
$(b)$ Mycorrhiza is a symbiotic association of fungi,such as $(4)$ Glomus,with plant roots.
$(c)$ Biocontrol agents include fungi like $(2)$ Trichoderma,which are used to treat plant diseases.
$(d)$ Biogas production involves methanogenic bacteria like $(1)$ Methanobacterium.
Therefore,the correct matching is $(a-3, b-4, c-2, d-1)$.