The correct answer is: A. PRSQ
The U.S. soyabean is America’s singlemost lucrative export. American soyabeans are a major source of high protein sustenance in the developing world and when famine strikes.
Option B, PSRQ, is incorrect because it puts the phrase “American soyabeans are a major source of high protein sustenance” before the phrase “the U.S. soyabean is America’s singlemost lucrative export.” This is incorrect because the U.S. soyabean is America’s singlemost lucrative export, and American soyabeans are a major source of high protein sustenance.
Option C, RQPS, is incorrect because it puts the phrase “in the developing world” before the phrase “and when famine strikes.” This is incorrect because the phrase “in the developing world” describes where American soyabeans are a major source of high protein sustenance, and the phrase “and when famine strikes” describes when American soyabeans are a major source of high protein sustenance.
Option D, RQSP, is incorrect because it puts the phrase “American soyabeans are a major source of high protein sustenance” after the phrase “when famine strikes.” This is incorrect because the phrase “American soyabeans are a major source of high protein sustenance” describes what American soyabeans are, and the phrase “when famine strikes” describes when American soyabeans are a major source of high protein sustenance.