The correct answer is D. All of these.
The Sutlej, Pabbar, and Giri are the three major rivers of Shimla district. The Sutlej is the longest river in Himachal Pradesh, and it flows through the district from east to west. The Pabbar is a tributary of the Sutlej, and it flows through the district from north to south. The Giri is a tributary of the Pabbar, and it flows through the district from east to west.
The Sutlej is a major source of irrigation and drinking water for the district. It is also a popular destination for fishing and boating. The Pabbar and Giri are also important sources of irrigation and drinking water. They are also popular destinations for fishing and boating.
The Sutlej, Pabbar, and Giri are all beautiful rivers that play an important role in the economy and environment of Shimla district.