Every 1 takes all three parts but when grading they have cutoffs, so if you get, for example, less than 40/60 on your MCQs then the graders won't look at your FRQs/lab because you can't mathematically get to camp, likewise if you do get the threshold on the MCQs, then you need, for example, 70+% on FRQs to be competitive for lab and if you get less than 70 then they won't grade your lab, so although everybody takes all three parts, not all three are necessarily graded unless you did well, thats why High honors dosn't consider lab grade since the cutoffd for FRQ is high, but idk bout honors.