Modern Sponges Produce Spicules to Deter Predation, but as the Earliest

Modern sponges produce spicules to deter predation, but as the earliest animals they existed before any predators evolved; how might biologists interpret this observation?

A) Spicules were probably absent in the earliest sponges and evolved later as predation began.
B) Spicules performed other tasks in early sponges, possibly structural support, and were later modified for defense.
C) Spicules were present in some sponge species and absent in others; predation became a selection pressure that eliminated some species entirely.
D) All of the above are valid hypotheses.