Final answer:
US high school dropout rates have declined consistently since the last half of the twentieth century and early twenty-first century, influenced by educational policies and the job market's growing demand for higher education.
Step-by-step explanation:
In the last half of the twentieth century and first several years of the twenty-first century, US high school dropout rates have C) Declined consistently. This trend is indicated by data showing a reduction in dropout rates from the 1980s, where 14 percent of all public school children dropped out, with even higher rates amongst minority students. By introducing measures such as bilingual education programs, despite their costs and challenges, improvement in academic achievement among non-English speakers was noted, which likely contributed to a decline in dropout rates. Moreover, the increasing necessity for higher education in the job market has influenced education trends and dropout rates.