A number of psychologists have attempted to teach language to nonhuman primates. In most instances, the primates learned many signs or word symbols; they could not, however, communicate about abstract or hypothetical concepts. With respect to the elements of language reviewed in the textbook, the primates mastered _____, but not _____.A) morphemes; displacementB) morphemes; phonemesC) displacement; morphemesD) displacement; phonemes