As per Angus Maddison’s book, The World Economy : Historical Statistics, what…

Concept — share of world GDP at PPP. A country’s share of world GDP is its output written as a percentage of total world output. At purchasing power parity (PPP) every economy is valued in one common set of prices — Angus Maddison used 1990 international dollars — so the shares stay comparable across centuries instead of moving with exchange rates. Maddison’s The World Economy: Historical Statistics (OECD, 2003) reconstructs these shares back to the beginning of the Common Era, which is why it can be quoted for “ancient times” at all.

Application. In that reconstruction the benchmark for ancient times is the year 1 CE. Maddison places the Indian subcontinent’s output at about 32.9% of world GDP (PPP) at that benchmark — close to one-third of everything produced in the world. The official BPSC answer key selects the offered value 32%. Maddison’s underlying table gives about 32.9% for year 1 CE, so 32% should be read as the examination’s listed approximation, not as nearest-whole-number rounding (which would give 33%). Among the offered choices, 32% is therefore the source-keyed percentage for this benchmark.

Cross-check — how the share moves through Maddison’s benchmark years.

Reading the table. The series falls away from the year 1 CE benchmark and never returns to it, so the one-third level belongs to the earliest reading. About 12% is where the series stands in 1870, well inside the colonial period, and no benchmark year in the series reads 20% — it lies between the 1700 and 1820 readings. Because exactly one listed percentage matches the year 1 CE benchmark, neither the cumulative choice nor the residual choice applies. The same book is the source of the frequently quoted claim that India and China together produced roughly half of world output at the start of the Common Era.