Under the Comprehensible Input Hypothesis, how is L2 learned or acquired?

Under the Comprehensible Input Hypothesis, how is L2 learned or acquired?

• A. We can learn L2 by listening passively to long streams of speech.
• B. Input alone guarantees native-like fluency.
• C. Comprehensible input means perfectly understandable material.
• D. We learn or acquire L2 by connecting to prior knowledge; language not understood is L2 noise.

Answer: (D)