Option 1 -> The commercial prospects were recognized later by entrepreneurs who formed the Assam Tea Company in 1839, not by Robert Bruce in 1823.
Option 2 -> The Assam Tea Company acquired large tracts of land after its formation in 1839, not something Robert Bruce discovered in 1823.
Option 3 -> The passage explicitly states that Robert Bruce discovered wild tea plants growing in the forests of Assam in 1823.
Option 4 -> The first commercial tea garden was established in 1837 at Chabua, which came after Robert Bruce's 1823 discovery.
Hence, Option 3 -> Robert Bruce's discovery of wild tea plants in 1823 marked the beginning of tea cultivation in Assam, though commercial cultivation and systematic tea gardening came later -> correct