Which one of the following does NOT pass through the Kaziranga Nationa

Which one of the following does NOT pass through the Kaziranga National Park ?

The Brahmaputra river
The Diphlu river
National Highway No. 37
Railway track of Indian Railway
This question was previously asked in
UPSC CAPF – 2017
A major Railway track of Indian Railway does NOT pass through the core area of Kaziranga National Park.
Kaziranga National Park is a UNESCO World Heritage Site famous for its Rhinoceros population. It is bounded by geographical features and infrastructure, including the Brahmaputra River to the north and National Highway 37 to the south.
The Brahmaputra River forms the northern boundary of the park. The Diphlu River is one of the several rivers that flow *through* the park, originating from the Karbi Anglong hills. National Highway 37 runs along the southern boundary and is a significant issue due to animal crossings. While there are railway lines in the vicinity of Kaziranga, they do not pass through the main body of the national park itself, unlike the highway and rivers which directly impact or traverse the park area.