Which one of the following statements about all the four of Spongilla, Leech, Dolphin and Penguin is correct –

Question

( A ) Penguin is homoiothermic while the remaining three are poikilothermic
( B ) All are bilaterally symmetrical
( C ) Leech is fresh water form while all others are marine
( D ) Spongilla has special collared cells called choanocytes, not found in the remaining three