During the first year of Herbert Hoover's presidency (1929-1930), the most relevant achievement from the options provided would be:
D. Hoover regulated the business practices that had caused the depression.
While Hoover did not implement direct relief programs that created jobs in a significant way, he did take steps towards regulating business practices. However, it is worth noting that many of his responses to the Great Depression were criticized as insufficient and were not as immediately effective as needed.
Overall, Hoover's administration faced significant challenges during the early years of the Great Depression, and his actions were often viewed as inadequate by many contemporaries and historians.