What is the correct decreasing order of research paper publications among the…

Concept

A country's research output is measured by the absolute number of science and engineering (S&E) journal articles it publishes each year, as tracked by databases such as Scopus and reported in sources like the NSF Science & Engineering Indicators and the World Bank. Among emerging economies, this annual count scales broadly with the size of the national research system, so ranking countries means comparing their total yearly publication counts from largest to smallest.

Applying it to these four BRICS members

Using the most-cited annual figures for the period around this exam (Scopus / NSF, latest available), the four countries' approximate S&E article counts and resulting rank are:

Reading the rank column from largest to smallest gives the decreasing order China, India, Russia, South Africa.

Cross-check

China is consistently the single largest producer of research articles in the world, far ahead of every other developing economy. The NSF Science & Engineering Indicators record that India became the third-largest producer of S&E articles globally in 2017 (behind only China and the United States), which places India well ahead of Russia; Russia's annual output sits below India's but above South Africa's; and South Africa, with the smallest research base of the four, produces the fewest. This ordering is stable across Scopus, NSF and World Bank reporting.

Result

Decreasing order = China > India > Russia > South Africa, i.e. (B), (A), (D), (C).