The correct option is A Leucosolenia
Ascon type of canal system is the one with the flagellated spongocoel. It is the simplest type of canal system. In this type of canal system, water enters through ostia into spongocoel and excrete through osculum. Sponge with ascon type of canal system is called as asconoid sponge e.g., Leucosolenia.
Thus, the correct answer is option B.