Step 1: Group the options by the (A) pairing - two use (A)-(II), two use (A)-(IV).
Step 2: Verify the correct causal organism for (A) to select the (A)-(IV) family.
Step 3: Within that family, verify (B) to choose between (I) and (III), confirming (B)-(III).
Step 4: The correct match is (A)-(IV), (B)-(III), (C)-(II), (D)-(I) (Option 4).