The correct answer is option 1, which states that only statement 1 and 2 are correct. Let`s analyze each statement to understand why:

Statement 1: The large-scale exploitation of groundwater is done with the help of tube wells. This statement is correct because tube wells are commonly used to extract water from underground sources.

Statement 2: The demand for groundwater started increasing with the advent of the green revolution. This statement is also correct. The green revolution, which happened during the 1960s and 1970s, led to significant increases in agricultural production through the introduction of high-yield crop varieties, modern farming techniques, and the increased use of irrigation. This in turn led to a higher demand for groundwater for irrigation purposes.

Statement 3: The total replenishable groundwater reserves are highest in the hilly tracts of Sikkim, Nagaland, and Tripura. This statement is not mentioned in the given explanation, so we cannot determine its correctness from the information provided.

Therefore, the correct answer is option 1, which states that only statement 1 and 2 are correct.