A student measures the volume of a cork.
He puts some water into a measuring cylinder and then one glass ball. He puts the cork and then a second,
identical glass ball into the water as shown.
Diagram 1 shows the first water level.
Diagram 2 shows the water level after one glass ball is added.
Diagram 3 shows the water level after the cork and the second glass ball are added.
What is the volume of the cork?
A 30 cm3 B 40 cm3 C 50 cm3 D 100 cm3