Why do I keep missing SAT punctuation questions
It shows up as a sentence with a blank between two ideas. The four choices differ only in the punctuation.
The trap
Most students read the sentence for sound, and all four versions sound fine out loud. A pause in that spot is natural, whatever mark sits there. The ear treats a comma, and a however fenced off by commas, as reasonable ways to mark that pause. What the ear cannot hear is that both halves are complete sentences. A lone comma has never been allowed to hold two of those together. The version built on however catches the strongest students. However feels like but, and but would have worked.
The rule
Test each half on its own. If both could stand as sentences, the join needs a period, a semicolon, or a comma with a conjunction. However is not a conjunction, so a comma on either side of it does not count.
If it keeps happening
If this one has fired on three practice tests running, punctuation is still being chosen by ear. More reading will not change that. It earns a lesson at any score, because it does not thin out as the score climbs. It sits in the early modules and in the hardest one alike.
Start with the free Diagnostic.
One short form. Within 24 hours you get it in writing: where the score stands and what to fix first.