What national park in Surat Thani features a massive ancient freshwater lake created by limestone formations?

• A Erawan
• B Khao Yai
• C Kaeng Krachan
• D Khao Sok ✓

Khao Sok National Park contains Cheow Lan Lake, a 165-square-kilometre reservoir surrounded by towering limestone karst formations, one of the oldest evergreen rainforests in the world.