The chamber common to all the types of canal system of sponges is

The correct answer is Paragastric cavity.

To understand why this option is correct, let us examine the structure and functioning of the canal system in sponges (phylum Porifera):

1. The Canal System: Sponges possess a unique water circulatory system, known as the canal system or aquiferous system, which plays a vital role in food gathering, respiratory gas exchange, and excretion. Water enters the sponge body through minute pores called ostia and exits through a larger opening called the osculum.

2. Types of Canal Systems: Sponges exhibit different types of canal systems depending on their structural complexity, ranging from the simple Asconoid type to the more complex Syconoid and Leuconoid types.

3. The Central Chamber: Regardless of the complexity of the canal system, all the water entering the sponge's body eventually converges into a large central cavity. This central chamber is lined by flagellated cells called choanocytes (or pinacocytes depending on the type and region) and is known as the paragastric cavity (also commonly referred to as the spongocoel or atrium). From this central cavity, water is expelled out of the body through the osculum.

4. Evaluating Other Options:
- Incurrent canals and excurrent canals are specialized pathways for water flow that vary in presence and arrangement depending on the complexity of the sponge (for instance, simple Asconoid sponges lack distinct incurrent and excurrent canals).
- Radial chambers (flagellated chambers) are specific to Syconoid and Leuconoid systems and are not present in the simpler Asconoid canal system.
- Therefore, the paragastric cavity is the only common central chamber present in all types of canal systems in sponges.