Read the passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 2...

Read the passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.

        Vietnam is ranked third globally by rare-earth mining potential and is increasingly courted as supply chains recalibrate. These elements underpin smartphones, cancer therapies, and renewable-energy technologies. Yet China still dominates the chain – about 63% of mining, 85% of processing, and 92% of magnet production – giving Beijing geopolitical leverage; in 2010, it even threatened export curbs to Japan. As the green transition accelerates and trade frictions persist, alternative sources gain salience; if supply chains fragment further, investors will prize jurisdictions offering credible governance and throughput.

        Rare earths are not always “rare”: they occur widely but seldom in high-grade clusters, which makes extraction expensive. Global reserves are estimated at roughly 120 million tons, with China holding 44 million, Brazil 22 million, Vietnam 20 million, and Russia 18 million. Vietnam’s known points – Dong Pao (Lai Chau), Muong Hum (Lao Cai), and the North Nam Xe system – are influential. Although reserves are substantial, deposits remain dispersed, extraction is costly, and domestic processing trails regional leaders. In short, scale exists, but bottlenecks persist.

        Environmental externalities are non-trivial. Waste rock and tailings can leach toxic substances into soils and aquifers if poorly contained. China’s experience is instructive: the Yellow River was threatened by mining-related waste, and in Guangdong, acid leaks damaged rice fields, streams, and canals. In response to health and ecological concerns, China tightened oversight and reduced output from 2012 onward. If analogous safeguards are not enforced elsewhere, communities may face similar risks, and remediation can become prohibitive.

        Vietnam’s constraints are well-documented: firms lack deep-processing technology and often complete only a fraction of the steps required for export-grade output. Enterprises reportedly reach about 40% of necessary processing – far below the Ministry of Industry and Trade’s 95% threshold. Resolution No. 10 acknowledges the sector’s importance but is short on specific mechanisms. The state has introduced pro-investment measures. These have included tax incentives, streamlined licensing, and industrial zones dedicated to mining and processing. Under CPTPP, projects must deliver “net benefits,” while VKFTA/EVFTA open pathways for joint ventures or wholly foreign-owned firms. By 2022, 108 FDI projects had been registered, totaling roughly US$4.9 billion.

(Adapted from Vietnam Briefing, “Rare Earth Mining in Vietnam: Industry Overview,” April 13, 2023)

Question 23. Which of the following is NOT mentioned in paragraph 3 as an environmental harm or risk?

A. Threats to a major river supplying millions of people

B. Acid leaks damaging rice fields, streams, and canals

C. Toxic substances leaching into groundwater systems and soil

D. Large-scale deforestation in Vietnam’s Central Highlands