To solve this problem, we need to match the organisms in List I with their corresponding excretory structures in List II.$\newline$Let's analyze each organism and their excretory structures:$\newline$• $$Taenia (A):$\newline$ - Taenia, a type of tapeworm, uses flame cells for excretion.$\newline$ - Flame cells are specialized cells that function in osmoregulation and excretion.$\newline$ - Therefore, Taenia corresponds to flame cells (III).$\newline$• $$Paramoecium (B):$\newline$ - Paramoecium, a unicellular organism, uses contractile vacuoles for excretion.$\newline$ - Contractile vacuoles help in expelling excess water and waste products.$\newline$ - Therefore, Paramoecium corresponds to contractile vacuole (II).$\newline$• $$Periplaneta (C):$\newline$ - Periplaneta, commonly known as the cockroach, uses urecose glands for excretion.$\newline$ - Urecose glands help in the excretion of nitrogenous wastes.$\newline$ - Therefore, Periplaneta corresponds to urecose gland (IV).$\newline$• $$Pheretima (D):$\newline$ - Pheretima, commonly known as the earthworm, uses nephridia for excretion.$\newline$ - Nephridia are tubular excretory structures that help in osmoregulation and excretion.$\newline$ - Therefore, Pheretima corresponds to nephridia (I).$\newline$Based on the analysis, the correct matching is:$\newline$A->III, B->II, C->IV, D->I$\newline$This corresponds to Option 3.