An $X$ reproduces in such great numbers that the water may appear red,producing red tides and killing large marine animals like $Z$. $X$ belongs to $Y$. Identify $X$,$Y$,and $Z$.

• A
  $X$-Gonyaulax; $Y$-Dinoflagellates; $Z$-Fishes
• B
  $X$-Paramecium; $Y$-Protozoa; $Z$-Crocodiles
• C
  $X$-Trypanosoma; $Y$-Protozoa; $Z$-Frogs
• D
  $X$-Plasmodium; $Y$-Euglenoids; $Z$-Oysters