The correct answer is "true."
The Harappan civilization developed in northern India instead of in the Deccan because the northern plains had better, more fertile soil.
We can say theoretically that is true because one of the major issues of the Harappa civilization is that they did not leave any records, that is why Historians know little about them.
The Harappans are also known as the Indus River civilization. They settled in the banks of the Indus River in northern India for the many benefits it represented for them.
The Deccan is located in southern India, and although there are rivers down there such as the Kavari and the Godavari, the region is drier than the north and has arid regions.