To analyze the results of changes in voting rights in the constitutions of 1788 and 1790, the second option, "the constitution of 1790 allowed all white males to vote for the first," is the most accurate in a historical context.
The 1788 constitution generally established voting rights that were more restrictive, often favoring landowning men and excluding various groups, including enslaved individuals and women. By 1790, many states began to expand suffrage primarily to all white male citizens, reflecting a broader shift in the understanding of who was entitled to participate in the democratic process.
The first option regarding power dynamics between the low country and the backcountry in relation to enslaved Africans being granted voting rights is not accurate, as enslaved individuals did not have voting rights.
The third option about military service being a qualification is also somewhat misleading, as it oversimplifies the understanding of voting qualifications at the time.
Overall, the option highlighting the expansion of voting rights to all white males captures the essence of the changes in voting rights between the two constitutions more effectively than the others.