Arrange the following in the correct sequence in the evolution of the nervous system:
$(a)$ Formation of a centralised nervous system.
$(b)$ Diffused nervous system in $Hydra$.
$(c)$ Formation of a ganglion.
$(d)$ Nervous system is lacking in sponges.

• A
  $(d)$,$(b)$,$(c)$ and $(a)$
• B
  $(a)$,$(d)$,$(b)$ and $(a)$
• C
  $(b)$,$(a)$,$(d)$ and $(c)$
• D
  $(c)$,$(d)$,$(a)$ and $(b)$