What are the main characteristics of poriferans?

I- They are the simplest invertebrates due to the little differentiated cells.
II- They are all aquatic and mostly marine.
III- They are mobile and move around.
IV- They have a soft and elastic body, with an internal skeleton formed by spines called spicules or by soft and flexible fibers of spongin.
V- Water circulates through the interior of the animal, facilitated by coanocytes, which are cells that have small hairs called flagella that, when they move, make the water circulate through the ducts and reach the central cavity.
a) I, II, and IV are correct.
b) II, III, and V are correct.
c) I, IV, and V are correct.
d) I, II, IV, and V are correct.