Pick out the correct statements :

a) In sponges choanocytes line the spongocoel and canals.

b) Fertilisation is internal and development is indirect in sponges.

c) Sponges exhibit cellular level of organization as cells in them are arranged as loose cell aggregates.

d) All sponges are asymmetrical, i.e., any plane that passes through the centre does not divide them into equal halves.