Disguised unemployment generally means

The correct answer is C. Disguised unemployment is a situation where people are counted as employed, usually on the land, but some of them add nothing to output. Their marginal productivity is zero or close to it, so withdrawing them would not reduce total production. The classic case is a farm family of five working a field that needs only three.

• A is wrong. Large open unemployment is a different concept, measured through surveys such as NSSO's usual status estimates, and it is visible rather than disguised.
• B is wrong. Lack of alternative jobs explains why surplus workers stay on the land, but it is a cause, not the definition.
• D is wrong. Low productivity is a broader feature of many workers and may reflect low wages or underemployment. The specific idea here is zero marginal product.

Core concept: Disguised unemployment is associated with Joan Robinson and with Nurkse's work on surplus labour in agriculture. It links to Mains questions on agrarian distress, rural non-farm employment, and the Lewis model of surplus labour transfer to industry.

Trap: Candidates confuse it with underemployment or low productivity (D). The key word is zero marginal productivity, meaning the worker could be withdrawn without any loss of output.