Explanation:

Only statements 1,2&4 are correct.

• The Razakars were a paramilitary force that advocated for the Nizam’s sovereignty and resisted the Indian invasion. They were accused of committing atrocities against the Hindu population and the Telangana rebels, who wanted land reforms and democracy.

• Operation Polo ended with the surrender of the Nizam on September 18, 1948. He signed an instrument of accession, joining India as a princely state. He was later appointed as the Rajpramukh (governor) of Hyderabad until 1956, when the state was reorganized along linguistic lines. 

• The United Nations did not intervene in the conflict, as it was considered an internal matter of India. However, Pakistan protested against India’s action and accused it of violating international law and human rights.

• In November 1947, Hyderabad signed a standstill agreement with India, which continued all previous arrangements except for the stationing of Indian troops in the state. The agreement was meant to last for one year, during which a final settlement would be reached. However, India accused Hyderabad of violating the agreement by importing arms, seeking foreign recognition, and supporting subversive activities.

Hence option 3rd is correct.