Answer : 2. "ऐसे दुर्लभ पादप और प्राणी जिनको खतरे की आशंका है "
Explanation :

The "Red Data Book" is a list of rare plants, animals, fungi and other organisms that are considered to be at maximum risk of extinction. It contains information on the status, distribution, and conservation of these species. Through the Red Data book, the conservation needs of these organisms are understood and necessary steps are planned for their protection.