The correct answer is A. 1960s.
Tea industry in Bihar was started in the 1960s. The first tea garden in Bihar was established in 1962 at Dalsinghsarai. The tea industry in Bihar has grown significantly since then, and there are now over 100 tea gardens in the state. The tea industry is a major source of employment in Bihar, and it contributes significantly to the state’s economy.
Option B is incorrect because the tea industry in Bihar was not started in the 1970s. The first tea garden in Bihar was established in 1962, and the tea industry has grown significantly since then.
Option C is incorrect because the tea industry in Bihar was not started in the 1980s. The first tea garden in Bihar was established in 1962, and the tea industry has grown significantly since then.
Option D is incorrect because the tea industry in Bihar was not started in the 1990s. The first tea garden in Bihar was established in 1962, and the tea industry has grown significantly since then.