Which of the following is the longest range in the lesser Himalayas?

Correct option is B

The Pir Panjal Range is the longest range in the Lesser Himalayas: 

• Location: The Pir Panjal Range runs through the states of Jammu and Kashmir and Himachal Pradesh. 
• Elevation: The range has an average elevation of 5,000 meters above sea level. 
• Rivers: The Jhelum, Kishanganga, and Chenab rivers flow through the range. 
• Location relative to the main Himalayan range: The Pir Panjal Range separates from the main Himalayan range near the Sutlej River. It forms a divide between the Beas and Ravi rivers on one side and the Chenab on the other. 
• Other ranges in the Lesser Himalayas: Other ranges in the Lesser Himalayas include the Dhaula Dhar and the Mahabharat ranges. 

Incorrect options explanation:

Karakoram Range, Mountain system, south-central Asia. Extending 300 mi (480 km) from eastern Afghanistan to the Kashmir region, it is one of the highest mountain systems in the world; its loftiest peak is K2, at 28,251 ft (8,611 m) the world's second highest peak.

The Zanskar range spans 250 kilometres (160 mi) from the Karcha (Suru) River near Kargil in the northwest to Tso Kar in the southeast. The range separates Indus Valley from the Zanskar Valley. The range is divided from the main Himalaya by the Stod, Tsarap and Zanskar Valleys.

The Ladakh Range is regarded as a southern extension of the Karakoram Range, which runs for 230 miles (370 km) from the confluence of the Indus and Shyok rivers in Baltistan to the Tibetan border of Ladakh in the southeast. The southern extension of the Ladakh Range is called the Kailash Range, especially in Tibet.