The correct option is B All of the above
The snail has a shell which can be very different in size and shape depending on the species of snail. The shells serve as a way to protect snails from the environment and even from predators in some cases. Snails do possess a visceral mass, where the internal organs are embedded. There is a ventral muscular foot which allows them to move forward. There is contracting and expanding in this muscle that allows them to move.
So, the correct answer is option D.