A measuring cylinder holds some water. A small metal block is lowered gently into the water and then taken out. Next, a piece of plastic is fixed to the metal block, and the block is once more lowered gently into the water. The diagrams show the measuring cylinder at each stage of this procedure. What is the volume of the piece of plastic?
- A$10\,\text{cm}^3$
- B$25\,\text{cm}^3$
- C$70\,\text{cm}^3$
- D$80\,\text{cm}^3$