In an experiment, two-year-old boys and their fathers made pie dough together using rolling pins and other utensils. Each father-son pair used a rolling pin that was distinctively different from those used by the other fatherson pairs, and each father repeated the phrase "rolling pin" each time his son used it. But when the children were asked to identify all of the rolling pins among a group of kitchen utensils that included several rolling pins, each child picked only the one that he had used. Which one of the following inferences is most supported by the
information above?

A. The children did not grasp the function of a rolling pin.
B. No two children understood the name "rolling pin" to apply to the same object.
C. The children understood that all rolling pins have the same general shape.
D. Each child was able to identify correctly only the utensils that he had used.
E. The children were not able to distinguish the rolling pins they used from other rolling pins.