Final answer:
In the given question, if APQR corresponds to ASTU, the statement that must be true is PQ = ST.
Step-by-step explanation:
In the given question, it is stated that APQR corresponds to ASTU. To determine which statement must be true, we can compare the corresponding sides.
From APQR to ASTU, we can observe that PQ corresponds to ST, so statement A) PQ = ST must be true.