Psychologists Have Conducted More Research on Language Comprehension Than on Language

Psychologists have conducted more research on language comprehension than on language production. Which of the following students provides the best explanation for this discrepancy?

A) Tina: "Psychologists find language comprehension to be more interesting from the perspective of social interactions."
B) Nayan: "Researchers find it easier to conduct research on language comprehension, because they can easily vary the material that participants hear or see."
C) Garth: "Researchers in the discipline of speech therapy have already conducted the relevant research on language production."
D) Louise: "Language production was the major topic of research just after the cognitive approach became popular; in the last decade, language comprehension has become the major topic of research."