A.I. Explanation:

Option 1: "They can learn languages more easily due to mature brain development."

Explanation: This option is incorrect because the text indicates that individuals who learn a second language later in life find it more difficult, not easier. The phrase 'learning a second language can be much more difficult' contradicts the idea of ease due to mature brain development.

Option 2: "Their brains use the same areas as when they learned their first language."

Explanation: This option is incorrect as the text states that for individuals learning a second language later, the brain designates a second adjacent area to process the new language, indicating that different areas are used rather than the same areas.

Option 3: "Their brains allocate a new, distinct area to learn the second language."

Explanation: This option is correct because the text explicitly states that Hirsche's research shows that for individuals learning a second language later in life, the brain allocates a new, distinct area to process the new language. This aligns directly with the main idea presented in the text.

Option 4: "They are more likely to learn the second language simultaneously and effortlessly."

Explanation: This option is incorrect because the text mentions that individuals who are not exposed to a second language until later in life often struggle with learning it, contrasting with the effortless learning described for children raised in bilingual environments.