The Irish Potato Famine in the Mid-1840s Was Caused by a Heterotrophic

The Irish potato famine in the mid-1840s was caused by a heterotrophic protist,Phytophthora infestans,which was successful in widespread infection of potato plants,largely because it was

A) a fungus, which has filaments very similar to water and slime molds.
B) a protozoan, with flagella, and swimming to potato plants in wet seasons, engulfing and digesting the potato cells.
C) a diatom, with a silica shell allowing it to survive the soil conditions in which potatos grow as specialized roots.
D) a red algae, able to perform photosynthesis, allowing its cells to spread from the coast to potato farm fields.
E) a water mold, and its soft, fleshy filaments benefitted from several rainy seasons.