Statement 1: 1000 litres = $1m^3$.

• This is correct. 1 cubic meter ($m^3$) is equal to 1000 liters.

Statement 2: 1 metric ton = $1000$ kg.

• This is correct. 1 metric ton is equal to 1000 kilograms.

Statement 3: 1 hectare = $10000$ $m^2$.

• This is correct. 1 hectare is defined as 10,000 square meters.

Thus, all the statements are correct.

Answer: D. 1, 2 and 3