Option 1 -> Bajaj Auto is a private sector company owned by the Bajaj Group.
Option 2 -> TISCO (Tata Steel) is a private sector enterprise owned by the Tata Group.
Option 3 -> Bharat Heavy Electricals Limited (BHEL) is a public sector undertaking fully owned by the Government of India.
Option 4 -> Gujarat Alkalies Limited is a joint sector enterprise with shared ownership between Gujarat State government and private shareholders.
Hence, Gujarat Alkalies Limited -> is a classic example of joint sector industry where both the state government and private investors jointly own and manage the company, combining the strengths of both public and private sectors -> correct