Step 1: Classification of human rights.
Human rights are commonly classified into generations based on their nature and historical development.
Step 2: Nature of the rights mentioned.
The right to development and the right to a healthy environment are collective rights that emphasize solidarity, sustainable development, and shared responsibilities of States.
Step 3: Identification of the generation.
Such collective and solidarity-based rights fall within the category of third generation rights.
Step 4: Conclusion.
Hence, the correct answer is (C) Third generation rights.