The correct answer is (a) T.C.S.
Tata Consultancy Services (TCS) is an Indian multinational information technology services and consulting company headquartered in Mumbai, Maharashtra. It is the largest Indian IT services company, the second largest IT services company in the world by revenue, and the largest employer in India with over 460,000 employees. TCS provides business consulting, technology, and outsourcing services to more than 2,000 clients in over 46 countries.
Wipro Limited is an Indian multinational information technology, consulting, and business process services company headquartered in Bangalore, Karnataka. It is the third largest Indian IT services company by revenue, after Tata Consultancy Services and Infosys. Wipro provides information technology, consulting, business process outsourcing, engineering, and manufacturing services to clients in over 60 countries.
ITC Limited is an Indian multinational conglomerate company headquartered in Kolkata, West Bengal. It is the largest cigarette manufacturer in India and the sixth largest in the world. ITC also has interests in the FMCG, hotels, paper, packaging, and agri-business sectors.
Idea Cellular is an Indian multinational telecommunications services company headquartered in Mumbai, Maharashtra. It is the second largest mobile network operator in India by subscribers, after Bharti Airtel. Idea Cellular provides GSM and LTE mobile services to over 400 million subscribers in over 22 circles in India.