The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Harappans manufactured a lot of copper and bronze objects. Evidence suggests that Khetri mines of Rajasthan were one of the major sources of copper for Harappans. However, different pattern of impurities has been noticed in copper objects found. For example, the objects at Lothal are free from arsenic and Khetri copper had arsenic, thus the copper procured for manufacturing objects at Lothal was from somewhere else.