Why does the author ask the question, "How do such evergreen plants escape intracellular freezing (freezing within cells) and tissue disestruction when temperatures may drop to -40℃ or colder ?” in the passage?

• To introduce an account of the ways evergreen plants protect themselves from the cold
• To suggest that losing their leaves would allow evergreens to escape damage from the cold
• To point out that scientists do not fully understand how evergreens survive cold temperatures
• To emphasize that studying evergreens may hold the key to understanding how all forest plants survive cold temperatures

This is a multiple choice.