Six-Year-Old Demetri and 4-Year-Old Lucien's Mother Gave Each Boy a Glass

Six-year-old Demetri and 4-year-old Lucien's mother gave each boy a glass of juice with their lunch, but Demetri asked her to switch the juice to another taller and narrower glass. After she poured the liquid from the original glass into the tall glass, Lucien said angrily, "Now Demetri gets more juice than me!" Lucien is displaying a lack of

A) conservation.
B) irreversibility.
C) hierarchical classification.
D) dual representation.