__________ is the most often cited of theory of second language acquisition.

• A. Transformationalist
• B. Krashen's Monitor Model
• C. Functionalist
• D. Interactionist

Answer: (B)

Krashen’s Monitor Model is the most frequently cited framework in the study of how people learn a second language. It foregrounds a distinction between what learners subconsciously acquire and what they learn about rules, and it argues that meaningful, comprehensible input just beyond the learner’s current level (i+1) is the main driver of acquisition. The model also introduces ideas like the natural order of acquisition, the role of the affective filter in shaping how learners receive input, and the idea that the monitor can guide edits in output when time and focus on form are available. This combination of influential concepts shaped many theories, research agendas, and classroom approaches, which is why it appears so often in overviews of SLA theory. Other options contribute valuable perspectives—Transformationalist ideas come from Chomsky’s grammar, Functionalist views emphasize language use and structure, and Interactionist views stress learning through social interaction—but none have been cited as consistently across studies and textbooks to the same extent as Krashen’s model.