Wasn't the constitution ratified in 1788?
However, the operation of the Constitution didn't commence until March 1789 [1] [2]. Prior to that commencement, government still operated under the Articles of Confederation. The question is poorly worded, if they're asking for when the federal government began operating under the Constitution; but it's also poorly worded if they're asking for when the ninth state ratified it.
[1] https://supreme.justia.com/cases/federal/us/18/420/ [2] https://tile.loc.gov/storage-services/service/ll/usrep/usrep...
That sums up roughly 95% of daily practice in US trials and appeals!
"(p.s. thanks to the smart readers who noticed I initially put the wrong date down, and who also noticed that "ratified" is somewhat indeterminate when it comes to the Constitution. But the real LSAT is unlikely to make those kinds of mistakes; there's only 1 correct answer, and it's definitely correct.)"
Feel free to make pull requests if you notice other errors or have suggestions for improvement: https://github.com/gpdowney/lightweightLSAT