The main centre of chemical industry is _________.
The chemical industry refers to the company producing industrial chemicals. Such industry converts various raw materials to different products. It uses raw materials like air, water, minerals, etc. Chemical industries of India are located in many places such as in Mumbai, Nagpur, Ajmer, Srinagar, Guwahati, Raipur, etc. But no such industry is majorly available at Kolkata, Hyderabad and Chennai.
Thus the correct option is A.