The following is missing for the question to be complete:
A. steven pinker
B. john watson
C. Noam chomsky
D. B.F. Skinner
Answer: Noam Chomsky
Explanation: It is a theory put forward by Noam Chomsky that talks about the speed at which children adopt and learn a language. The theory he puts forward is better known as the Language Acquisition Device (LAD), which is a tool for quickly learning languages by children. Of course it is a hypothetical tool in the brain. Using LAD, as Chomsky explained, children are capable of learning any language, depending on their environment. All humans are therefore born with an innate knowledge of what language is and what it is made of, so it is an innate language learning tool.