Match the columns:

Column-$I$	Column-$II$
$(a)$ Mycorrhiza	$(1)$ Rhizobium
$(b)$ Bt	$(2)$ Nucleopolyhedrovirus
$(c)$ Root nodules	$(3)$ Phosphorus
$(d)$ Baculovirus	$(4)$ Bt-Cotton

$(A)$ The correct matches are as follows:
$(a)$ Mycorrhiza is a symbiotic association between fungi and roots of higher plants, which helps in the absorption of $(3)$ Phosphorus.
$(b)$ Bt refers to Bacillus thuringiensis, which is used to create $(4)$ Bt-Cotton.
$(c)$ Root nodules are the site of nitrogen fixation in leguminous plants, formed by $(1)$ Rhizobium.
$(d)$ Baculovirus are pathogens that attack insects and other arthropods, specifically the genus $(2)$ Nucleopolyhedrovirus.
Therefore, the correct sequence is $(a-3, b-4, c-1, d-2)$.