The correct answer is: Option D. Ambala is the headquarters of Northern Railway Zone.
Northern Railway Zone is one of the 17 railway zones of Indian Railways. It is headquartered in Ambala, Haryana. The zone covers the states of Haryana, Punjab, Himachal Pradesh, Jammu and Kashmir, Uttarakhand, Delhi, Uttar Pradesh, Rajasthan, and parts of Madhya Pradesh and Bihar.
The zone has a total route length of 7,324 km, of which 6,304 km is electrified. It has 1,040 stations, of which 200 are major stations. The zone has a total of 1,20,000 employees.
The zone operates a fleet of over 5,000 locomotives and 10,000 coaches. It carries over 1.5 billion passengers and 50 million tonnes of freight annually.
The zone was formed on 1 April 1952, by merging the Ambala and Delhi divisions of the erstwhile North Western Railway. The zone was initially headquartered in Delhi, but it was shifted to Ambala in 1956.
The zone has six divisions: Ambala, Delhi, Ferozepur, Lucknow, Moradabad, and Allahabad. The zone has a number of important railway stations, including New Delhi Railway Station, Old Delhi Railway Station, Hazrat Nizamuddin Railway Station, Anand Vihar Terminal, and Sarai Rohilla Railway Station.
The zone is also home to a number of important railway workshops, including the Ambala Railway Workshop, the Delhi Railway Workshop, the Allahabad Railway Workshop, and the Lucknow Railway Workshop.
The zone is a major contributor to the Indian economy. It provides employment to a large number of people and helps in the movement of goods and people across the country.