Consider the following statements:
1. The Harappan economy was based on agriculture.
2. In Indus Valley Civilization, elaborate drainage systems are found.
3. In Indus Valley Civilization, sugarcane was unknown.
4. In Kotdiji, the pre-Harappan settlement has not been found.
Which of the above statements is/are correct?
(a) 1 and 2 only (b) 2 and 3 only
(c) 3 and 4 only (d) 1, 3 and 4 only