Which of the Following Is an Example of a Project

Which of the following is an example of a project approach activity for a preschool class?

A) A class spends several days on various activities about the plumbing in their building, including a field trip to the basement to see how the water heater works.
B) At 9 AM every day, half the children in the class do sorting and counting activities while the other half work on an art project. After 20 minutes the groups switch.
C) All the children who are ready for literacy activities work in a group; those who are not ready play with the blocks.
D) The children work together painting a large cardboard box that they can use in pretend play to represent anything they want.