Step 1: Pleuron's retained lateral sclerite near the leg base is the epimeron.
Step 2: Tergum's posterior dorsal plate is the postnotum; sternum's hardened ventral plate is the eusternum.
Step 3: The basal leg sclerite linking to the pleuron is the trochantin.
\[ \boxed{\text{(A)-(IV), (B)-(III), (C)-(II), (D)-(I)}} \]