What does "internal mechanism" (Line 3, Para 3) mean

A．Its individualistic approach to language is meant to study the psychological processes of language acquisition.
B．The individualistic approach to language is mainly concerned with how language functions in society.
C．The study of language is sure to involve more than a single individual.
D．Psychological approach to language is concerned with the comprehension and production of speech.

A．To explain the need for an increased supply of gold.
B．To indicate the extent of United States mineral wealth.
C．To describe the mood when oil was first discovered.
D．To argue that gold was more valuable than oil.