Explanation:

• Workers who own and operate an enterprise to earn their livelihood are known as self -employed. More than half the workforce in India belongs to this category. Hence, (c) is the correct option.
• The construction workers are known as casual wage labourers; they account for 30 per cent of India’s workforce.
• Workers like the civil engineer working in the construction company account for 18 per cent of India’s workforce. They are known as regular salaried employees.