Option d is the correct answer The Harappan civilisation belongs to the Bronze Age civilisation and Harappans knew how to make copper and bronze tools. Iron was not known to the Harappan people. Iron came into existance in later vedic period. Important Tips Harappan civilisation The Indus Civilisation represents the first phase of urbanisation in India There are three phases of Harappan zCivilization Early Harappan 3000-2600 BCE Mature Harappan 2600-1900 BCE Late Harappan 1900-1700 BCE Fortification, wellplanned streets and lanes and drainages are noticed in the Harappan towns. The Harappans used baked and unbaked bricks, and stones for construction. The towns had a grid pattern and drainages were systematically built. Artefacts: Statues whether in stone, bronze or terracotta found in Harappan sites are refined. The stone statuaries found at Harappa and Mohenjodaro are excellent examples of handling three-dimensional volumes The art of bronze-casting was practised on a wide scale by the Harappans. Their bronze statues were made using the 'lost wax' technique in which the wax figures were first covered with a coating of clay and allowed to dry. terracotta representations of human form are crude in the Indus Valley