Manas National Park (Assam): Situated on the banks of the Manas River, it encompasses a range of ecosystems including grasslands, tropical evergreen forests, and semi-evergreen forests. Namdapha National Park (Arunachal Pradesh): This park boasts diverse vegetation zones, ranging from tropical evergreen forests at lower elevations to sub-alpine meadows at higher altitudes. Neora Valley National Park (West Bengal): This park covers a range of elevations with subtropical broadleaf forests at lower levels and temperate forests at higher reaches. The Valley of Flowers National Park (Uttarakhand): On the other hand, is situated at a high altitude (3352 to 3658 metres above sea level) and falls entirely within the temperate alpine zone, known for its meadows, low-growing vegetation, and cooler climate. Hence, option D is the correct Answer.