In the studies by Flavell (1999), children were presented with a box on which there were pictures of candy. Three and four-year-old children believed that the box contained candy. The children saw that the box contained crayons once it was opened

The three-year-old believed that other children would believe that the box contained crayons instead of candy. This demonstrates which principle?
A) The theory of mind
B) The false-belief principle
C) Underdevelopment of short-term memory
D) Conservation

B