Explanation:

The Zoological Survey of India has underlined some green rules for the living root bridges of Meghalaya to get the UNESCO World Heritage Site tag. Meghalaya CM Conrad K. Sangma pitched for UNESCO recognition as the hill State marked its 50th year of creation.

• A living root bridge is like a suspension bridge formed by guiding the pliable roots of the rubber fig tree (Ficus elastica) across a stream or river and allowing the roots to grow and strengthen over time.
• They are common in the southern part of the Northeast Indian state of Meghalaya.

Hence option 3rd is correct.