The correct answer is Muzaffarpur and adjoining areas.
Litchi is a famous fruit export from Bihar. It is primarily grown in Muzaffarpur and adjoining areas. The other options are incorrect. Patna is the capital of Bihar and is not a major producer of litchi. Bhagalpur is a city in the eastern part of Bihar and is not a major producer of litchi. Darbhanga is a city in the north-central part of Bihar and is not a major producer of litchi.
Muzaffarpur is a city in the north-central part of Bihar. It is the headquarters of Muzaffarpur district. The city is located on the banks of the Gandak River. Muzaffarpur is a major commercial and educational center. It is also a major producer of litchi. The litchi orchards in Muzaffarpur are spread over an area of about 10,000 hectares. The litchi season in Muzaffarpur starts from April and ends in June. The litchi from Muzaffarpur is known for its sweet taste and juicy flesh. It is exported to many countries, including the United States, the United Kingdom, and the Middle East.