NDP = _________.

Correct — C. Net always means gross minus depreciation, the wear and tear on the country's capital stock over the year.

NDP = GDP − depreciation

Depreciation is machinery, buildings and equipment used up in producing the year's output. It is inside GDP because GDP counts investment gross, so taking it out is exactly what turns a gross measure into a net one.

Net factor income from abroad is the other switch entirely, moving you between domestic and national rather than gross and net. So option (c).

Why the others are wrong

• (a)
  GDP + Net factor income from abroad — GDP + net factor income from abroad is GNP, not NDP. That addition takes you from domestic to national and leaves the measure gross.
• (b)
  GDP – Net factor income from abroad — GDP − net factor income from abroad runs the GNP relation backwards. It produces no standard aggregate, and it never touches depreciation.
• (d)
  GDP + Depreciation — GDP + depreciation goes the wrong way. Depreciation already sits inside GDP through gross investment, so adding it again double-counts capital consumption.

The national-income aggregates come from two independent switches, and an SSC question of this kind is always one switch.

Gross to net: subtract depreciation. GDP becomes NDP, GNP becomes NNP.

Domestic to national: add net factor income from abroad, what Indians earn abroad minus what foreigners earn in India. GDP becomes GNP, NDP becomes NNP.

Read which word changed in the option, net or national, and the formula follows.

Key facts

• NDP = GDP − depreciation.
• GNP = GDP + net factor income from abroad.
• NNP = GNP − depreciation.
• National income is NNP at factor cost, which is NNP at market price minus net indirect taxes.

Common traps

• Reaching for net factor income from abroad because the word net appears in both switches.
• Adding depreciation instead of subtracting it, which turns a net measure back into a gross one.

No directly related past PYQ was found.