The correct answer is: B. Baltoro glacier
The Baltoro Glacier is the second largest glacier in the Karakoram Range and the second largest glacier in the Himalayan region, after the Siachen Glacier. It is located in Gilgit-Baltistan, Pakistan, and is about 56 kilometers (35 mi) long. The Baltoro Glacier is a source of the Indus River.
The Siachen Glacier is the longest glacier in the Karakoram Range and the second longest glacier in the world outside the polar regions. It is located in the disputed region of Kashmir, between India and Pakistan. The Siachen Glacier is about 76 kilometers (47 mi) long and 3 kilometers (1.9 mi) wide at its widest point. The Siachen Glacier is a source of the Shyok River.
The Hispar Glacier is the third largest glacier in the Karakoram Range. It is located in Gilgit-Baltistan, Pakistan, and is about 60 kilometers (37 mi) long. The Hispar Glacier is a source of the Hunza River.
The Biafo Glacier is the fourth largest glacier in the Karakoram Range. It is located in Gilgit-Baltistan, Pakistan, and is about 62 kilometers (39 mi) long. The Biafo Glacier is a source of the Shyok River.