The correct answer is A. Gulab Singh.
Gulab Singh was the ruler of Jammu and Kashmir from 1846 to 1857. He was a Dogra Rajput and a general in the Sikh army. In 1846, he signed the Treaty of Amritsar with the British East India Company, which gave him control of Ladakh and the surrounding areas in exchange for a payment of 75 lakhs of rupees.
Ranbir Singh was the son of Gulab Singh and the ruler of Jammu and Kashmir from 1857 to 1885. He was a strong and capable ruler who expanded the territory of his kingdom. He also built many roads, bridges, and canals.
Pratap Singh was the son of Ranbir Singh and the ruler of Jammu and Kashmir from 1885 to 1925. He was a popular ruler who was known for his generosity and his love of music and poetry.
Hari Singh was the son of Pratap Singh and the ruler of Jammu and Kashmir from 1925 to 1950. He was the last ruler of Jammu and Kashmir before it became an Indian state. He signed the Instrument of Accession in 1947, which made Jammu and Kashmir a part of India.