Herbert Terrace Was Highly Critical of the Ape/language Work, Concluding

Herbert Terrace was highly critical of the ape/language work, concluding that the animals were simply imitating their trainers. Later work by others suggested that

A) all the other language-trained apes had also failed to use sign language any more spontaneously than did Terrace's chimpanzee Nim.
B) language-trained apes can use their signs or lexigrams as true symbols rather than simply as labels.
C) language-trained apes would sign only to their trainers rather than ever sign to other animals or to themselves.
D) Terrace was right.