What is the status of the hypothesis that language evolved as a by-product of overall intelligence?

a. It is supported by findings that total brain mass correlates highly with language ability.

b. It is supported by findings that teaching language to other primates causes an enormous amount of brain expansion.

c. It is contradicted by findings that brain damage has no effect on language.

d. It is contradicted by findings that some people have normal intelligence without language, and others have normal language despite mental retardation in many other regards.