(d) Primary sector, especially unorganized sector
The table shows the primary sector employs the maximum workers (232 million), of which 231 million are in the unorganized sector.
Read the "Total" column: Primary (232) > Tertiary (128) > Secondary (115). Within Primary, almost all workers (231 out of 232 million) are in the unorganized sector. This directly matches option (d). The textbook also confirms that primary sector remains the largest employer even now.