The order of priority of the following functional groups in the $IUPAC$ method of naming organic compounds is:
$(i) >C=O$
$(ii) -NH_2$
$(iii) -CN$
$(iv) -COOR$

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