The correct answer is (a) Bombay.
The Bombay High Court is the highest court of appeal in the state of Maharashtra and the Union Territory of Dadra and Nagar Haveli and Daman and Diu. It has jurisdiction over 100 districts in Maharashtra, 1 district in Dadra and Nagar Haveli, and 2 districts in Daman and Diu.
The Allahabad High Court is the highest court of appeal in the state of Uttar Pradesh. It has jurisdiction over 75 districts in Uttar Pradesh.
The Calcutta High Court is the highest court of appeal in the state of West Bengal. It has jurisdiction over 23 districts in West Bengal.
The Guwahati High Court is the highest court of appeal in the states of Assam, Arunachal Pradesh, Nagaland, Manipur, Meghalaya, Mizoram, Tripura, and Sikkim. It has jurisdiction over 27 districts in Assam, 8 districts in Arunachal Pradesh, 7 districts in Nagaland, 9 districts in Manipur, 7 districts in Meghalaya, 8 districts in Mizoram, 8 districts in Tripura, and 4 districts in Sikkim.
The Bombay High Court has the largest jurisdiction because it has jurisdiction over the most districts.