Match Column-$I$ with Column-$II$ and select the correct option:

Column-$I$	Column-$II$
$(a)$ $Bt$ Cotton	$(i)$ Gene therapy
$(b)$ Adenosine deaminase deficiency	$(ii)$ Cellular defense
$(c)$ $RNAi$	$(iii)$ Detecting $HIV$ infection
$(d)$ $PCR$	$(iv)$ $Bacillus$ $thuringiensis$

• A
  $(iv), (i), (ii), (iii)$
• B
  $(iii), (ii), (i), (iv)$
• C
  $(ii), (iii), (iv), (i)$
• D
  $(i), (ii), (iii), (iv)$