Explanation:

- A worker in a factory is participating in manufacturing goods or providing services, both of which contribute to the national income.

- A software engineer working with Reliance is involved in the IT sector, generating software products or services that are part of the national income.

- A seasonal farmer in Punjab, through crop production, contributes to the agricultural sector, adding to the national income.

- All the above options represent activities that add value to a country's economy, hence all contribute to the national income.

- Correct Answer: Option 4 - All the above