The correct answer is A. Sabour.
The tissue culture laboratory of banana cultivation for promoting high banana production was established at Sabour in 1986. The laboratory is located at the Indian Institute of Horticultural Research (IIHR), Regional Station, Sabour. The laboratory is equipped with state-of-the-art facilities for tissue culture of banana. The laboratory has been successful in developing a number of banana varieties that are resistant to diseases and pests. The laboratory has also been successful in developing a number of banana varieties that are high-yielding. The laboratory has been instrumental in promoting the cultivation of banana in India.
Option B, Mithapur, is incorrect because the tissue culture laboratory of banana cultivation for promoting high banana production was not established at Mithapur.
Option C, Purnia, is incorrect because the tissue culture laboratory of banana cultivation for promoting high banana production was not established at Purnia.
Option D, Bihar Sharif, is incorrect because the tissue culture laboratory of banana cultivation for promoting high banana production was not established at Bihar Sharif.